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Abstract: Recent large-scale multiomics studies suggest that genetic factors influence the chemical individuality of donated blood. To examine this concept, we performed metabolomics analyses of 643 blood units from volunteers who donated units of packed red blood cells (RBCs) on 2 separate occasions. These analyses identified carnitine metabolism as the most reproducible pathway across multiple donations from the same donor. We also measured l-carnitine and acyl-carnitines in 13 091 packed RBC units from donors in the Recipient Epidemiology and Donor Evaluation study. Genome-wide association studies against 879 000 polymorphisms identified critical genetic factors contributing to interdonor heterogeneity in end-of-storage carnitine levels, including common nonsynonymous polymorphisms in genes encoding carnitine transporters (SLC22A16, SLC22A5, and SLC16A9); carnitine synthesis (FLVCR1 and MTDH) and metabolism (CPT1A, CPT2, CRAT, and ACSS2), and carnitine-dependent repair of lipids oxidized by ALOX5. Significant associations between genetic polymorphisms on SLC22 transporters and carnitine pools in stored RBCs were validated in 525 Diversity Outbred mice. Donors carrying 2 alleles of the rs12210538 SLC22A16 single-nucleotide polymorphism exhibited the lowest l-carnitine levels, significant elevations of in vitro hemolysis, and the highest degree of vesiculation, accompanied by increases in lipid peroxidation markers. Separation of RBCs by age, via in vivo biotinylation in mice, and Percoll density gradients of human RBCs, showed age-dependent depletions of l-carnitine and acyl-carnitine pools, accompanied by progressive failure of the reacylation process after chemically induced membrane lipid damage. Supplementation of stored murine RBCs with l-carnitine boosted posttransfusion recovery, suggesting this could represent a viable strategy to improve RBC storage quality., (© 2024 American Society of Hematology. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

Purpose Preterm infants frequently require red blood cell (RBC) transfusions in neonatal intensive care units (NICU). Storage RBCs undergo many changes during storage periods. We aimed to compare the hemoglobin (Hb) correction effect according to the period of RBC storage and investigate the factors influencing Hb correction. Methods This retrospective study reviewed the medical records of 289 patients who received RBC transfusion more than once in the NICU of Kosin University Gospel Hospital between February 2006 and March 2016. The subjects were classified into two storage groups: short-term (≤7 days, n=88) and long-term (>7 days, n=201), according to the period of RBC storage. We checked Hb levels by complete blood cell count tests conducted within 2 days before and 5 to 9 days after the first transfusion. We compared the Hb difference between the two groups and analyzed the factors influencing Hb correction. Results Excluding the use of an invasive ventilator, there was no significant difference between the two groups in terms of clinical characteristics. There was no significant difference in the Hb correction effect between the two groups (P=0.537). Birth weight greater than 1,500 g, higher weight at transfusion, and larger volume of transfusion were significant prognostic factors affecting greater changes in Hb. In addition, surgeryexperience, higher Hb level at transfusion, and additional blood tests were found to be significantly associated with less changes in Hb. Conclusion The RBC storage period did not affect the Hb correction effect. The Hb correction effect may be diminished in infants with lower birth weight and lower weight at transfusion under unstable clinical conditions.

Plasmodium parasites need to find red blood cells (RBCs) that, on the one hand, expose receptors for the pathogen ligands and, on the other hand, maintain the right geometry to facilitate merozoite attachment and entry into the red blood cell. Both characteristics change with the maturation of erythrocytes. Some Plasmodia prefer younger vs. older erythrocytes. How does the life evolution of the RBC affect the invasion of the parasite? What happens when the RBC ages? In this review, we present what is known up until now.

Background: The mortality of trauma patients requiring massive transfusion to treat hemorrhagic shock approaches 17% at 24 hours and 26% at 30 days. The use of stored RBCs is limited to less than 42 days, so older RBCs are delivered first to rapidly bleeding trauma patients. Patients who receive a greater quantity of older RBCs may have a higher risk for mortality.Methods and Materials: Characterizing blood age exposure requires accounting for the age of each RBC unit and the quantity of transfused units. To address this challenge, a novel Scalar Age of Blood Index (SBI) that represents the relative distribution of RBCs received is introduced and applied to a secondary analysis of the Pragmatic, Randomized Optimal Platelet and Plasma Ratios (PROPPR) randomized controlled trial (NCT01545232, https://clinicaltrials.gov/ct2/show/NCT01545232). The effect of the SBI is assessed on the primary PROPPR outcome, 24-hour and 30-day mortality.Results: The distributions of blood storage ages successfully maps to a parameter (SBI) that fully defines the blood age curve for each patient. SBI was a significant predictor of 24-hour and 30-day mortality in an adjusted model that had strong predictive ability (odds ratio, 1.15 [1.01-1.29], p = 0.029, C-statistic, 0.81; odds ratio, 1.14 [1.02-1.28], p = 0.019, C-statistic, 0.88, respectively).Conclusion: SBI is a simple scalar metric of blood age that accounts for the relative distribution of RBCs among age categories. Transfusion of older RBCs is associated with 24-hour and 30-day mortality, after adjustment for total units and clinical covariates. [ABSTRACT FROM AUTHOR]

This study initially focused on characterizing the aging process of red blood cells by correlating the loss of hemoglobin and the translocation of phosphatidylserine (PS) in expired human red blood cells, hRBCs. Five pre-storage, leukoreduced hRBC units in AS-5 solution were stored between 1 and 6 °C for 42 days. Aliquots from each of these units were stained with Annexin-V FLUOS, which binds to externalized PS, and the hemoglobin within the cells was placed in a methemoglobin state with sodium nitrite, metHb. These aliquots were subsequently sorted into four sub-populations, ranging from no PS expression to high PS expression using a BD FACS ARIAIII. Each of these sub-fractions were introduced into the cell tracking velocimetry apparatus which measured both the magnetically-induced and the gravity-induced velocity. Subsequently, the samples were removed from the cell tracking velocimetry instrument and characterized using the Multisizer 4e Coulter Counter. From the magnetically-induced velocity, the amount of hemoglobin, in pg Hb per cell can be determined, and using an average value of the density of RBCs, the size can be determined. For the PS negative sub-fraction of RBCs, the size of the RBC was as expected but the average hemoglobin, Hb, content was below the threshold which defines anemia. In contrast, unexpected results were observed with the various levels of expression of PS. First, virtually all of the PS expressing cells were significantly smaller, on the order of 1 micron, than a normal RBC after 42 days of storage; yet the density of these small cells/microvesicles was such that they had settling velocities similar to normal-sized RBCs. Further, while the total amount of Hb per small cell/microvesicle was only approximately 25% of the full-sized RBCs, the volume of these small cells/microvesicles is only 1/200 of the PS negative RBCs. This suggests that these PS expressing cells are shrunken RBCs, or shrunken microvesicles from RBCs that concentrated the Hb internally. These results suggest not only a relationship between the loss of hemoglobin and the amount of PS exposed on the cellular outer wall, but also a mechanism by which these aged RBCs break down. It is not known at this time whether this is an artifact of storage or similar mechanisms occur in circulation within the human body. [ABSTRACT FROM AUTHOR]

The hematological effects of chronic radiation exposure in males of the pygmy wood mouse (Apodemus uralensis Pall., 1811) from the East Urals radioactive trace (EURT) area were assessed, taking into account population abundance and reproductive status (immature, ripening, and mature yearlings). For this purpose, we analyzed the morpho-functional characteristics of erythrocytes (red cell indices [MCV, MCH, MCHC], red cell count, activity of antioxidant enzymes [GSH-Px, CAT], lipid peroxidation, glycolysis, osmotic resistance, methaemoglobin content) and blood plasma components (free hemoglobin, total lipids, total cholesterol, and glucose) in the background territory and the EURT area; these areas have a density of soil contamination with 90Sr of 12,851 and 198 kBq × m−2, respectively (four and two order of magnitude higher than the background value). The data indicate the “hyperfunctional” state of the erythrocyte, aimed at activation of the gas transport function of blood in the radioactive environment. This, as a consequence, determines the insufficiency of energy supply of the cell defense system necessary to maintain the structural integrity of the membrane. Intensification of membrane lipid peroxidation, reduction of osmotic resistance and GSH-Px activity in red cells, an increase in the degree of intravascular hemolysis, and tendency towards erythropenia indicate the processes of accelerated aging of erythrocytes and their more pronounced destruction in the circulatory bed. The level of the hematological response increased with increasing radiation burden and was more pronounced with a large population size. The interaction effect of “overpopulation” and “radioactive pollution” was observed to a lesser degree for ripening males, and was very small for sexually mature animals. Immature males from the EURT head part with internal whole-body radiation doses of 0.0045-0.35 mGy/day can be considered as the most sensitive group to the factors synergy, including radiation damage and overabundance population. [ABSTRACT FROM AUTHOR]

Prolonged storage will alter the biophysical properties of red blood cells (RBCs), and it decreases the quality of stored blood for blood transfusion. It has been known that less deformable aged RBCs can be separated by margination, but the recognition of the storage time from the separation efficiency of the stiff RBCs is still a challenge. In this study, we realized enhanced separation of aged RBCs from normal RBCs by controlling the channel cross section and demonstrated that the storage time can be deduced from the percentage of the separated RBCs in the stored RBCs. This separation technology helps to reveal the regulation of time on the RBC aging mechanism and offer a new method to separate stiffened cells with high efficiency. [ABSTRACT FROM AUTHOR]

Background: It is uncertain whether the duration of red-cell storage affects mortality after transfusion among critically ill adults.Methods: In an international, multicenter, randomized, double-blind trial, we assigned critically ill adults to receive either the freshest available, compatible, allogeneic red cells (short-term storage group) or standard-issue (oldest available), compatible, allogeneic red cells (long-term storage group). The primary outcome was 90-day mortality.Results: From November 2012 through December 2016, at 59 centers in five countries, 4994 patients underwent randomization and 4919 (98.5%) were included in the primary analysis. Among the 2457 patients in the short-term storage group, the mean storage duration was 11.8 days. Among the 2462 patients in the long-term storage group, the mean storage duration was 22.4 days. At 90 days, there were 610 deaths (24.8%) in the short-term storage group and 594 (24.1%) in the long-term storage group (absolute risk difference, 0.7 percentage points; 95% confidence interval [CI], -1.7 to 3.1; P=0.57). At 180 days, the absolute risk difference was 0.4 percentage points (95% CI, -2.1 to 3.0; P=0.75). Most of the prespecified secondary measures showed no significant between-group differences in outcome.Conclusions: The age of transfused red cells did not affect 90-day mortality among critically ill adults. (Funded by the Australian National Health and Medical Research Council and others; TRANSFUSE Australian and New Zealand Clinical Trials Registry number, ACTRN12612000453886 ; ClinicalTrials.gov number, NCT01638416 .). [ABSTRACT FROM AUTHOR]

Background Blood trauma caused by continuous-flow left ventricular assist devices (CF-LVADs) has been associated with device thrombosis and anemia. Accurate in vivo quantification of erythrocyte turnover and its contribution to CF-LVAD complications have yet to be elucidated. Methods We investigated the age (lifespan) of circulating erythrocytes in subjects with CF-LVAD. Erythrocyte lifespan is a quantitative indicator of in vivo erythrocyte turnover that can be accurately derived from measurement of the exhaled carbon monoxide (CO) level. Sixty non-smoking subjects were prospectively enrolled: 25 had a CF-LVAD without thrombosis; 10 had a CF-LVAD with thrombosis; and 25 were normal controls. End-tidal breath CO levels were measured and used to calculate erythrocyte lifespan. Results The mean erythrocyte lifespan was significantly shorter in CF-LVAD subjects with (29.7 ± 14.9 days) compared to those without (65.0 ± 17.3 days) device thrombosis ( p < 0.0001). The lifespans in these 2 groups were significantly shorter compared with normal controls (96.0 ± 24.9 days, both p < 0.0001). A receiver operator curve demonstrated high sensitivity-specificity for use of erythrocyte lifespan to detect device thrombosis (AUC = 0.94). In addition, all CF-LVAD subjects had low hemoglobin (11.8 ± 2.0 g/dl), and their anemia was normochromic normocytic with elevated mean reticulocyte counts. Erythrocyte lifespan correlated significantly with mean corpuscular hemoglobin concentration ( r = 0.56, p = 0.0005) and red cell distribution width ( r = –0.65, p < 0.001), but not with reticulocyte count ( r = 0.27, p = 0.32). Conclusions Erythrocyte lifespan is substantially reduced in subjects with a CF-LVAD, which was more pronounced in the presence of device thrombosis. The etiology of anemia in CF-LVAD was primarily due to accelerated erythrocyte aging. Further studies are needed to determine whether erythrocyte lifespan could provide a practical means of detecting subtle pre-clinical thrombosis. [ABSTRACT FROM AUTHOR]

Aging is a natural phenomenon, which is characterised by progressive physiological changes at cellular and organ level. During aging, the defence mechanism of an organism declines over the period of time. The aim of this study was to investigate the biological efficacy of berberine in D-galactose induced aging rat models. For the study, rats were divided into four groups: Control received only vehicle, BBR received berberine orally, D-Gal received D-galactose subcutaneously and BBR + D-Gal received D-galactose and berberine simultaneously. D-galactose treatment increased the pro-oxidants such as malondialdehyde (MDA) level, protein carbonyl, plasma membrane redox system (PMRS) and advanced oxidation protein products (AOPP) in the erythrocytes or plasma. It reduced the anti-oxidant level such as reduced glutathione (GSH), ferric reducing ability of plasma (FRAP), plasma thiols, sialic acid and membrane transporters like Na + /K + ATPase and Ca 2+ ATPase activity in the erythrocyte membrane. Co-treatment of berberine in D-galactose induced aging rat models restored pro-oxidants and anti-oxidants in erythrocytes. Berberine also restored the activity of Na + /K + ATPase and Ca 2+ ATPase in the erythrocyte membrane. On the basis of these findings, we suggest that berberine treatment could attenuate erythrocyte aging in rats through stabilisation of the redox equilibrium., (© 2023 Walter de Gruyter GmbH, Berlin/Boston.)

Alterations at the level of plasma membrane are reported to play an important role in cellular senescence. The present study was undertaken to correlate cellular senescence, membrane transport processes and organismal aging. To achieve this objective activities of membrane linked Na+/K + ATPase (NKA), Na+/H+ exchanger (NHE) and correlation with membrane hydrxyperoxide level, sialic acid content and membrane protein oxidation was studied in density-gradient fractionated young and old erythrocytes from 4 and 24 month old Wistar rats. The results reveal that cellular aging within the tissue is associated with significant decrease in activities of NKA and NHE of senescent erythrocytes in comparison to younger cell population of same age group. The result shows that impaired ion homeostasis due to altered membrane transporters including functional and compositional changes may be one of the reasons responsible behind rat erythrocyte aging. [ABSTRACT FROM AUTHOR]

Aging in Brazil has increased due to the combination of factors such as declining fertility and mortality rates. In this perspective, the objective of this study was to investigate the relationship between respiratory muscle strength and motor activity in elderly people in social groups. It is an analytical research with cross-sectional design and a quantitative approach, performed in Living Group for Senior Citizens in the municipality of Vitoria da Conquista / BA, with a sample of 31 elderly. The instruments used were: sociodemographic information, health status, assessment of motor activity, assessment of ins-piratory muscle strength and maximum expiratory. Data were analyzed using descriptive statistical analysis and application of chi-square test, with 5% significance level. In the assessment of motor activity there was a predominance of elderly people with limitations in balance activities (61.3%), sitting and standing (87.1%), walking (96.7%) and squat (80.6%). The mean values of MIP was 55.6 (± 21.0) cmH20, MEP was 71.3 (± 22.0) cmH20. With the application of chi-square test, there was no statistically significant difference between activity limitation sitting and standing with MIP (p=0.000), between activity limitation to squat and MIP (p=0.001) and between equilibrium limitation and MEP (p=0.003). It was found in this study was no association between the limited motor skills and breathing capacity. [ABSTRACT FROM AUTHOR]

The impact of transfusing fresher vs older red blood cells (RBCs) on patientimportant outcomes remains controversial. Two recently published large trials have provided new evidence. We summarized results of randomized trials evaluating the impact of the age of transfused RBCs. We searched MEDLINE, EMBASE, CINAHL, the Cochrane Database for Systematic Reviews, and Cochrane CENTRAL for randomized controlled trials enrolling patients who were transfused fresher vs older RBCs and reported outcomes of death, adverse events, and infection. Independently and in duplicate, reviewers determined eligibility, risk of bias, and abstracted data. We conducted random effects meta-analyses and rated certainty (quality or confidence) of evidence using the GRADE approach. Of 12 trials that enrolled 5229 participants, 6 compared fresher RBCs with older RBCs and 6 compared fresher RBCs with current standard practice. There was little or no impact of fresher vs olderRBCs onmortality (relative risk [RR], 1.04; 95% confidence interval [CI], 0.94-1.14; P 5 .45; I 2 5 0%, moderate certainty evidence) or on adverse events (RR, 1.02; 95% CI, 0.91-1.14; P 5 .74; I 2 5 0%, low certainty evidence). Fresher RBCs appeared to increase the risk of nosocomial infection (RR, 1.09; 95% CI, 1.00-1.18; P 5 .04; I 2 5 0%, risk difference 4.3%, low certainty evidence). Current evidence provides moderate certainty that use of fresher RBCs does not influence mortality, and low certainty that it does not influence adverse events but could possibly increase infection rates. The existing evidence provides no support for changing practices toward fresher RBC transfusion. [ABSTRACT FROM AUTHOR]

BACKGROUND Phosphatidylserine (PS) exposure facilitates the removal of red blood cells (RBCs) from the circulation, potentially contributing to the loss of stored RBCs after transfusion, as well as senescent RBCs. Activation of the P2X7 receptor by extracellular adenosine 5′-triphosphate (ATP) can induce PS exposure on freshly isolated human RBCs, but whether this process occurs in stored RBCs or changes during RBC aging is unknown. STUDY DESIGN AND METHODS RBCs were processed and stored according to Australian blood banking guidelines. PS exposure was determined by annexin V binding and flow cytometry. Efficacy of P2X antagonists was assessed by flow cytometric measurements of ATP-induced ethidium+ uptake in RPMI 8226 cells. Osmotic fragility was assessed by lysis in hypotonic saline. RBCs were fractionated by discontinuous density centrifugation. RESULTS ATP (1 mmol/L) induced PS exposure on RBCs stored for less than 1 week. This process was near-completely inhibited by the P2X7 antagonists A438079 and AZ10606120 and the P2X1/P2X7 antagonist MRS2159 but not the P2X1 antagonist NF499. ATP-induced PS exposure on RBCs was not dependent on K+, Na+, or Cl− fluxes. ATP did not alter the osmotic fragility of stored RBCs. ATP-induced PS exposure was similar between RBCs of different densities. ATP-induced PS exposure was also similar between RBCs stored for less than 1 week or for 6 weeks. CONCLUSION The propensity of RBCs to undergo P2X7-mediated PS exposure does not alter during in vivo and ex vivo aging. Thus, P2X7 activation is unlikely to be involved in the removal of senescent RBCs or stored RBCs after transfusion. [ABSTRACT FROM AUTHOR]

The age of erythrocyte concentrates (EC) in transfusion medicine and the adverse outcomes when transfusing long-term-stored EC are highly controversial issues. Whereas the definition of a short-term-stored EC or a long-term-stored EC is unclear in clinical trials, data based on in vitro storage assays can help defining a limit in addition of the expiration date. The present review merges together these data in order to highlight an EC age cut-off and points out potential misleading consideration. The analysis of in vitro data highlights the presence of reversible and irreversible storage lesions and demonstrates that red blood cells (RBC) exhibit two limits during storage: one around 2 weeks and another one around 4 weeks of storage. Of particular importance, the first lesions to appear, i.e. the reversible ones, are per se reversible once transfused, whereas the irreversible lesions are not. In clinical trials, the EC age cut-off for short-term storage is in general fewer than 14 days (11 ± 4 days) and more disperse for long-term-stored EC (17 ± 13 days), regardless the clinical outcomes. Taking together, EC age cut-off in clinical trials does not totally fall into line of in vitro aging data, whereas it is the key criteria in clinical studies. Long-term-stored EC considered in clinical trials are not probably old enough to answer the question: “Does transfusion of long-term-stored EC (older than 4 weeks) result in worse clinical outcomes?” Depending on ethical concerns and clinical practices, older EC than currently assayed in clinical trials should have to be considered. These two worlds trying to understand the aging of erythrocytes and the impact on patients do not seem to speak the same language. [ABSTRACT FROM AUTHOR]

This paper presents experimental and numerical studies of erythrocyte stretching, with a focus on the aging of red blood cells in an in vitro environment during storage. The experimental studies were performed using optical tweezers. The laser beam was used to pull and stretch a cell sedimented on a flat surface. A force calibration was obtained via a comparison of the experimental data with results from finite element simulations of the cell stretching. The experiments were performed using blood samples from blood bank donations made by three donors. The experiments were performed over 21 days of storage, and the estimate erythrocyte membrane shear modulus during this period increased from 2.5 to 13 μN/m. [ABSTRACT FROM AUTHOR]

Background Some effects of the red blood cell ( RBC) storage lesion are well documented whereas others are not. Whether a period of room temperature hold ( RTH) during RBC production enhances the RBC storage lesion has remained controversial. In this study, we compared whole blood ( WB)-derived RBCs produced after 24-h RTH with rapidly cooled ( RC) RBCs and tested them for classical metabolic markers and signs of oxidative damage. Study design and methods SAGM- RBCs were prepared from mixed and split pairs ( n = 12) of WB units. RBCs prepared after a 24-h period of RTH on day+1 after collection ( RTH- RBCs) were compared with RC- RBCs. All RBCs were stored at 4°C for 42 days with assay of in vitro variables on days+1, +15, +22, +29 and +42. The study examined standard quality parameters, glutathione, catalase and superoxide dismutase ( SOD) activities, and indicative markers of oxidative cell damage including post-translational haemoglobin modification, malondialdehyde (MDA), and phosphatidylserine expression. Results RTH- RBCs exhibited decreased levels of potassium (1·98 ± 0·26 vs. 5·23 ± 0·65 mmol/l) and of 2,3-diphosphoglycerate (2,3- DPG) on day+1 compared with RC- RBCs. Haemolysis rate on day+42 was higher in RTH- RBCs than in RC- RBCs (0·52 ± 0·13 vs. 0·37 ± 0·12%). The phosphatidylserine expression amounted to 0·25 ± 0·20% in RTH- RBCs and 0·07 ± 0·12% in RC- RBCs. Haemoglobin modification was not different between both RBC groups. RTH- RBCs showed slightly higher MDA concentration on days +29 and +42. Conclusions RC- RBCs and RTH- RBCs show only small differences of classical in vitro parameters and no relevant differences in antioxidative metabolism and oxidative haemoglobin modification. These findings do not explain the loss observed in in vivo survival studies with RBCs. [ABSTRACT FROM AUTHOR]

Red blood cells ( RBCs) destined for transfusion can be refrigerator-stored for up to 42 days prior to transfusion. Our studies in mice and dogs suggest that transfusion of older, stored RBCs, but not fresh RBCs, produce acute elevations in circulating pro-inflammatory cytokine levels. Although our study in healthy adult human volunteers failed to demonstrate a pro-inflammatory cytokine response following transfusion of RBCs stored for 40-42 days, a recent study in preterm infants suggests that RBC transfusions are associated with a pro-inflammatory response. Thus, whether RBC transfusions, particularly of older, stored RBCs, result in a pro-inflammatory cytokine response, is still an unresolved issue. Animal studies suggest this to be true, yet human studies have yet to demonstrate definitively that such an inflammatory response occurs. Potential explanations for this include differences between human and animal biology, the dose of RBCs transfused and baseline differences in levels of inflammation. This review will summarize the currently available evidence and approaches to resolving whether transfusions of older, stored RBCs are associated with inflammation in recipients. [ABSTRACT FROM AUTHOR]

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

The circadian clock and the hypoxic signaling pathway play critical roles in physiological homeostasis as well as in pathogenesis. The bi-directionality of the interaction between both pathways has been shown on physiological and only recently also on molecular level. But the consequences of a disturbed circadian rhythm for the hypoxic response and the cardiovascular system have never been addressed in any organism. Here we show that the hypoxic response of animals subjected to chronodisruption is reduced by approximately 30%, as reflected by decreased expression levels of hypoxia inducible factor 1 and its down-stream target genes e rythropoietin, responsible for the generation of red blood cells (RBC) and v ascular endothelial growth factor, which is essential for proper vascularization. Beside malformations of their vascular beds, chronodisrupted animals surprisingly revealed elevated numbers of senescent erythrocytes under normoxic conditions, due to a reduced clearance rate via apoptosis. Over-aged erythrocytes in turn are characterized by decreased oxygen transport capacities and an increased tendency for aggregation, explaining the higher mortality of chronodisrupted animals observed in our study. The present study shows for the first time that chronodisruption strongly interferes with the hypoxic signalling cascade, increasing the cardiovascular risk in zebrafish due to elevated proportions of senescent erythrocytes. The results might shed new light on the etiology of the increased cardiovascular risk observed among shiftworkers. [ABSTRACT FROM AUTHOR]

Background and Objectives Refrigerated storage of red blood cells ( RBCs) induces numerous changes that may target the cells for erythrophagocytosis following transfusion. The influence of storage upon the phagocytosis of unseparated and fractionated young and old stored RBCs was investigated using two in vitro quantitative phagocytosis assays. Materials and Methods Leucocyte-depleted RBC units were sampled at day 1 or 42 of storage. Young and old RBCs were fractionated at day 1 by density centrifugation and stored in paediatric packs for up to 42 days. RBCs were labelled with the fluorescent dye PKH26 and incubated with the human monocytic cell line THP-1. Erythrophagocytosis was quantified by flow cytometry and plate fluorometric assays. Results A higher proportion of THP-1 cells phagocytosed RBCs stored for 42 days compared with 1 day (41% and 24% respectively; P < 0·0001). This was associated with an increased mean number of RBCs phagocytosed per THP-1 cell (5·2 ± 0·6 and 3·3 ± 0·2 respectively; P < 0·002). Erythrophagocytosis of fractionated young and old RBCs increased with longer storage duration up to 28 days ( P < 0·05). However, no significant differences were observed between erythrophagocytosis of young and old RBCs. Conclusion The susceptibility of stored RBCs to erythrophagocytosis significantly increased with longer storage time of the RBC units. Storage duration of RBCs had a greater influence on in vitro erythrophagocytosis than the chronological age of the RBCs at donation. [ABSTRACT FROM AUTHOR]

Background Studies are currently under way examining whether the age of stored red blood cells ( RBCs) affects clinical outcome in transfusion recipients. The effects of storage duration on the RBC storage lesion are well documented, while fewer studies are available regarding the effect of RBC production method. In this study, we compared in vitro RBC quality variables and markers of inflammatory response in apheresis and whole blood ( WB)-derived RBCs, specifically those prepared after an overnight room temperature hold ( RTH) of WB. Study Design and Methods SAGM RBCs, prepared from WB after overnight RTH (n = 10), were compared to SAGM RBCs prepared using an apheresis device ( Alyx, n = 10). As a control, SAGM RBCs were also prepared within 2 hours of WB collection (2-hr WB, n = 10). All RBCs were stored at 4° C for 42 days with weekly assay of in vitro variables, cytokines and/or chemokines, and neutrophil activation after incubation with RBC supernatant. Results RTH WB RBCs exhibited decreased levels of 2,3-diphosphoglycerate acid (2.3 μmol/g hemoglobin [ Hb] ± 2.1 vs. 13.7 ± 1.3 μmol/g Hb) and morphology (160 ± 10 vs. 192 ± 5) on Day 1 and increased hemolysis (0.45 ± 0.21% vs. 0.31 ± 0.09%) and microparticles (6.1 ± 2.8/103 RBCs vs. 3.9 ± 1.1/103 RBCs) on Day 42 compared to apheresis RBCs. Gro-α and ENA-78 cytokine levels were significantly higher in RTH WB than Alyx RBCs during storage. CD11b expression was highest in neutrophils exposed to supernatant from RTH WB RBCs (p < 0.05). Conclusion RBC preparation method has a meaningful effect on the RBC storage lesion, which should be taken into account in addition to length of storage. [ABSTRACT FROM AUTHOR]

Abstract: Vesicle formation is an integral part of the physiological erythrocyte aging process. Recent biophysical and immunochemical data have suggested that vesicles originate by the extrusion of membrane patches that, during aging, have become damaged and simultaneously enriched in removal signals. Thereby, vesiculation may serve to postpone the untimely removal of functional cells. As a first step toward the identification of the underlying mechanisms, we isolated erythrocyte-derived vesicles from plasma by fluorescence-activated cell sorting, analyzed their proteome by mass spectrometry, and compared this with the membrane proteomes of erythrocytes that were separated according to cell age. The presence of band 3 and actin in the vesicles together with the absence of almost all other integral membrane and cytoskeletal proteins, and the specific, aging-associated alterations in band 3 aggregation and degradation shown by proteomics as well as immunochemistry, all suggest that the erythrocyte aging process harbors a specific, band 3-centered mechanism for vesicle generation. The age-related recruitment of plasma proteins, proteins of the ubiquitin–proteasome system, and small G proteins to the erythrocyte membrane supports the hypothesis that modification of band 3 and/or degradation initiate vesiculation, and the subsequent recognition and fast removal of vesicles by the immune system. This article is part of a Special Issue entitled: Integrated omics. [Copyright &y& Elsevier]

We have recently developed a new technique to objectively identify erythrocyte cohorts of defined age in mouse blood. The technique (termed double in vivo biotinylation, DIB) involves an initial biotinylation of all erythrocytes in circulation, followed after a few days by a second biotinylation, at a lower density, that labels the biotin-negative erythrocytes that have entered since the first biotinylation. The proportions of biotinhigh, biotinlow, and biotinnegative erythrocytes are enumerated by flow cytometry. The DIB technique allows us to track age-related changes on erythrocyte cohorts (Protocol A), and to simultaneously identify very young and older erythrocyte populations in the blood (Protocol B). Using this technique, we have reexamined: i) the relationship between age and buoyant density of erythrocytes, ii) erythrocyte destruction through a random removal mechanism, and iii) the expression of phosphatidylserine on aging erythrocytes. We have also used the DIB technique to study age-related changes in the expression of various markers like CD47 and CD147 and green autofluorescence in aging erythrocyte populations. Copyright © 2012 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: Background: In vitro data suggest that erythrocytes undergo storage time-dependent degradation, eventuating in hemolysis. We hypothesize that transfusion of old blood, as compared with newer blood, results in a smaller increment in hematocrit. Methods: We performed an analysis of packed red blood cell transfusions administered in the surgical intensive care unit. Age of blood was analyzed as continuous, dichotomized at 14 days (old vs new), and grouped by weeks old. Results: A total of 136 U of packed red blood cells were given to 52 patients; 110 (80.9%) were 14 days old or more. A linear, inverse correlation was observed between the age of blood and the increment in hematocrit (r2 = −.18, P = .04). The increment in hematocrit was greater after transfusion of new as compared with old blood (5.6% vs 3.5%, respectively; P = .005). A linear relationship also was observed between the age of transfused blood in weeks and the increment in hematocrit (P = .02). Conclusions: There is an inverse relationship between the age of blood and the increment in hematocrit. The age of blood should be considered before transfusion of surgical patients with intensive care unit anemia. [Copyright &y& Elsevier]

The article discusses the aspect of erythrocyte's programmed cell death (PCD). It states the impact of age-related alterations of chemical and physical properties of the red blood cells (RBCs) to the behavior and performance of erythrocyte affecting blood transfusion. Moreover, it presents a study which shows the capacity of mature erythrocyte to self-destruct due to environmental changes.