Perioperative management of antithrombotics in elective intracranial procedures: systematic review, critical appraisal.

PURPOSE: Perioperative management of patients medicated with antithrombotics requiring elective intracranial procedures is challenging. We ought to (1) identify the clinical practice guidelines (CPGs) and recommendations (CPRs) on perioperative management of antithrombotic agents in elective intracranial surgery and (2) assess their methodological quality and reporting clarity. METHODS: The study was conducted following the 2020 PRISMA guidelines for a systematic review and has been registered (PROSPERO, CRD42023415710). An electronic search was conducted using PubMed, Scopus, and Google Scholar. The search terms used were "adults," "antiplatelets," "anticoagulants," "guidelines," "recommendations," "english language," "cranial surgery," "brain surgery," "risk of bleeding," "risk of coagulation," and "perioperative management" in all possible combinations. The search period extended from 1964 to April 2023 and was limited to literature published in the English language. The eligible studies were evaluated by three blinded raters, by employing the Appraisal of Guidelines for Research & Evaluation II (AGREE-II) analysis tool. RESULTS: A total of 14 sets of guidelines were evaluated. Two guidelines from the European Society of Anaesthesiology and one from the American College of Chest Physicians found to have the highest methodological quality and reporting clarity according to the AGREE-II tool. The interrater agreement was good with a mean Cohens Kappa of 0.70 (range, 46.5-94.4%) in the current analysis. CONCLUSION: The perioperative management of antithrombotics in intracranial procedures may be challenging, complex, and demanding. Due to the lack of high quality data, uncertainty remains regarding the optimal practices to balance the risk of thromboembolism against that of bleeding.

Composites in Aerospace and Mechanical Engineering.

An important step towards improving performance while reducing weight and maintenance needs is the integration of composite materials into mechanical and aerospace engineering. This subject explores the many aspects of composite application, from basic material characterization to state-of-the-art advances in manufacturing and design processes. The major goal is to present the most recent developments in composite science and technology while highlighting their critical significance in the industrial sector-most notably in the wind energy, automotive, aerospace, and marine domains. The foundation of this investigation is material characterization, which offers insights into the mechanical, chemical, and physical characteristics that determine composite performance. The papers in this collection discuss the difficulties of gaining an in-depth understanding of composites, which is necessary to maximize their overall performance and design. The collection of articles within this topic addresses the challenges of achieving a profound understanding of composites, which is essential for optimizing design and overall functionality. This includes the application of complicated material modeling together with cutting-edge simulation tools that integrate multiscale methods and multiphysics, the creation of novel characterization techniques, and the integration of nanotechnology and additive manufacturing. This topic offers a detailed overview of the current state and future directions of composite research, covering experimental studies, theoretical evaluations, and numerical simulations. This subject provides a platform for interdisciplinary cooperation and creativity in everything from the processing and testing of innovative composite structures to the inspection and repair procedures. In order to support the development of more effective, durable, and sustainable materials for the mechanical and aerospace engineering industries, we seek to promote a greater understanding of composites.

Predictors of 30-Day Postoperative Outcome after Elective Endovascular Abdominal Aortic Aneurysm Repair: A Tertiary Referral Center Experience.

BACKGROUND: We evaluated the 30-day postoperative outcome after elective endovascular aneurysm repair (EVAR) and the possible predictors for the 30-day postoperative outcome. MATERIALS: Demographics, medical history, laboratory values, intensive care unit (ICU) admission and 30-day complications classified as major (major adverse cardiovascular events (MACEs), acute kidney injury (AKI) and death of any cause) and minor (postimplantation syndrome (PIS), postoperative delirium (POD), urinary tract infection (UTI) and technical graft failure) were documented (March 2016 to February 2019). RESULTS: We included 322 patients. The majority were managed under general anesthesia (83%) with femoral cutdown (98.1%). Overall, 121 (37.5%) complications, mostly minor (n = 103, 31.9%), were recorded. In total, 11 patients (3.4%) developed MACEs, 5 (1.6%) experienced AKI and 2 (0.6%) died in the ICU. Moreover, 77 patients (23.9%) suffered from PIS, 11 from POD, 11 from UTI and 4 from technical graft failure. The multivariate logistic regression analysis revealed that aneurysm diameter (p = 0.01) and past smoking (p = 0.003) were predictors for complications. PAD was an independent predictor of MACEs (p = 0.003), preoperative neutrophil to lymphocyte ratio (NLR) of AKI (p = 0.003) and past smoking of PIS (p = 0.008), respectively. CONCLUSIONS: Our study showed that the 30-day morbidity after EVAR exceeded 35%. However, the majority of complications were minor, and the associated mortality was low. Aneurysm diameter and past smoking were independent predictors for postoperative outcome.

Hospitalization for acute heart failure during non-working hours impacts on long-term mortality: the REPORT-HF registry.

AIMS: Hospital admission during nighttime and off hours may affect the outcome of patients with various cardiovascular conditions due to suboptimal resources and personnel availability, but data for acute heart failure remain controversial. Therefore, we studied outcomes of acute heart failure patients according to their time of admission from the global International Registry to assess medical practice with lOngitudinal obseRvation for Treatment of Heart Failure. METHODS AND RESULTS: Overall, 18 553 acute heart failure patients were divided according to time of admission into 'morning' (7:00-14:59), 'evening' (15:00-22:59), and 'night' (23:00-06:59) shift groups. Patients were also dichotomized to admission during 'working hours' (9:00-16:59 during standard working days) and 'non-working hours' (any other time). Clinical characteristics, treatments, and outcomes were compared across groups. The hospital length of stay was longer for morning (odds ratio: 1.08; 95% confidence interval: 1.06-1.10, P < 0.001) and evening shift (odds ratio: 1.10; 95% confidence interval: 1.07-1.12, P < 0.001) as compared with night shift. The length of stay was also longer for working vs. non-working hours (odds ratio: 1.03; 95% confidence interval: 1.02-1.05, P < 0.001). There were no significant differences in in-hospital mortality among the groups. Admission during working hours, compared with non-working hours, was associated with significantly lower mortality at 1 year (hazard ratio: 0.88; 95% confidence interval: 0.80-0.96, P = 0.003). CONCLUSIONS: Acute heart failure patients admitted during the night shift and non-working hours had shorter length of stay but similar in-hospital mortality. However, patients admitted during non-working hours were at a higher risk for 1 year mortality. These findings may have implications for the health policies and heart failure trials.

The time-course linkage between hemolysis, redox, and metabolic parameters during red blood cell storage with or without uric acid and ascorbic acid supplementation.

Oxidative phenomena are considered to lie at the root of the accelerated senescence observed in red blood cells (RBCs) stored under standard blood bank conditions. It was recently shown that the addition of uric (UA) and/or ascorbic acid (AA) to the preservative medium beneficially impacts the storability features of RBCs related to the handling of pro-oxidant triggers. This study constitutes the next step, aiming to examine the links between hemolysis, redox, and metabolic parameters in control and supplemented RBC units of different storage times. For this purpose, a paired correlation analysis of physiological and metabolism parameters was performed between early, middle, and late storage in each subgroup. Strong and repeated correlations were observed throughout storage in most hemolysis parameters, as well as in reactive oxygen species (ROS) and lipid peroxidation, suggesting that these features constitute donor-signatures, unaffected by the diverse storage solutions. Moreover, during storage, a general "dialogue" was observed between parameters of the same category (e.g., cell fragilities and hemolysis or lipid peroxidation and ROS), highlighting their interdependence. In all groups, extracellular antioxidant capacity, proteasomal activity, and glutathione precursors of preceding time points anticorrelated with oxidative stress lesions of upcoming ones. In the case of supplemented units, factors responsible for glutathione synthesis varied proportionally to the levels of glutathione itself. The current findings support that UA and AA addition reroutes the metabolism to induce glutathione production, and additionally provide mechanistic insight and footing to examine novel storage optimization strategies.

Additive prognostic value of longitudinal myocardial deformation to SCORE2 in psoriasis.

Aims: Psoriasis has been associated with increased cardiovascular (CV) risk. We investigated whether markers of CV function and their change after treatment have a prognostic value for adverse outcomes. Methods and results: In a prospective study, at baseline and after 6 months of treatment with biological agents, we assessed in 298 psoriasis patients (i) left ventricular global longitudinal strain (GLS) and (ii) carotid-femoral pulse wave velocity (PWV), to evaluate their prognostic value for major adverse cardiovascular events (MACEs), including coronary artery disease, stroke, hospitalization for heart failure, and all-cause death over a 4-year follow-up period. During follow-up, 26 (8.7%) MACEs were recorded. By univariate analysis, decreasing absolute GLS values [hazard ratio (HR): 0.73, P < 0.001], decreasing GLS change after treatment (HR: 0.53, P = 0.008), and increasing PWV values (HR: 1.16, P = 0.049) were associated with adverse outcomes. Baseline GLS and its change post-treatment remained independent predictors of adverse events after adjusting for several confounders (P < 0.05). The addition of baseline GLS and its absolute change post-treatment to SCORE2 increased Harrell's C from 0.882 to 0.941. By multivariable analysis, for each 1% increase in absolute baseline GLS values, the risk of MACE decreased by 33% and for each 1% absolute increase of GLS post-treatment compared with the baseline value, the risk of MACE decreased by 58%. Conclusion: Global longitudinal strain has an independent and additive prognostic value to SCORE2 for adverse CV events in psoriasis, providing timely decision-making for intensive anti-inflammatory treatment and aggressive modification of risk factors to reduce CV risk.

Supplementation with uric and ascorbic acid protects stored red blood cells through enhancement of non-enzymatic antioxidant activity and metabolic rewiring.

Redox imbalance and oxidative stress have emerged as generative causes of the structural and functional degradation of red blood cells (RBC) that happens during their hypothermic storage at blood banks. The aim of the present study was to examine whether the antioxidant enhancement of stored RBC units following uric (UA) and/or ascorbic acid (AA) supplementation can improve their storability as well as post-transfusion phenotypes and recovery by using in vitro and animal models, respectively. For this purpose, 34 leukoreduced CPD/SAGM RBC units were aseptically split in 4 satellite units each. UA, AA or their mixture were added in the three of them, while the fourth was used as control. Hemolysis as well as redox and metabolic parameters were studied in RBC units throughout storage. The addition of antioxidants maintained the quality parameters of stored RBCs, (e.g., hemolysis, calcium homeostasis) and furthermore, shielded them against oxidative defects by boosting extracellular and intracellular (e.g., reduced glutathione; GSH) antioxidant powers. Higher levels of GSH seemed to be obtained through distinct metabolic rewiring in the modified units: methionine-cysteine metabolism in UA samples and glutamine production in the other two groups. Oxidatively-induced hemolysis, reactive oxygen species accumulation and membrane lipid peroxidation were lower in all modifications compared to controls. Moreover, denatured/oxidized Hb binding to the membrane was minor, especially in the AA and mix treatments during middle storage. The treated RBC were able to cope against pro-oxidant triggers when found in a recipient mimicking environment in vitro, and retain control levels of 24h recovery in mice circulation. The currently presented study provides (a) a detailed picture of the effect of UA/AA administration upon stored RBCs and (b) insight into the differential metabolic rewiring when distinct antioxidant "enhancers" are used.

Effect of prolonged storage on quality characteristics of recovered plasma: Is there an expiration date?

BACKGROUND: Although there are guidelines on industrial manufacture of plasma-derived medicinal products, there are no clear recommendations about plasma intended for fractionation, as there is no expiry time and the effect of prolonged storage on the activity of coagulation factors is unknown. STUDY AND DESIGN METHODS: A total of 237 units of plasma stored at -30°C in the National Blood Transfusion Centre for 1 year (62 units), 5 years (75 units), and 10 years (100 units) were studied. The effect of storage time was investigated by determining the activity of clotting factors FII, FV, FVII, FVIII, FIX, FX, FXI, FXII, FXIII using coagulometric methods and antithrombin III and fibrinogen with chromogenic assays, using System BCSR > XP (Siemens Healthcare diagnostics Marburg, Germany). Albumin was measured by Medilyzer (BX, Medicon). ABO blood group was recorded and correlated with the levels of FVIII. Comparison of values between one and five, 1 and 10 and 5 and 10 years of storage was performed via the SAS for Windows 9.4 software platform (SAS Institute Inc., NC, U.S.A.). RESULTS: Albumin, AT III, fibrinogen, FIX, FXI, FXII, and FXIII remain rather stable even after 10 years of storage. Levels of FII, FV, FVII, FVIII, and FX decreased after 5 years of storage. DISCUSSION: Our study is in agreement with all the previous studies and concludes that there is a putative usability of recovered plasma and some of its coagulation factors after many years of storage at the recommended temperature.

A COVID-19 outbreak among migrants in a hosting facility in Greece, April 2020.

In April 2020, a coronavirus disease 2019 outbreak was identified among migrants/refugees in Greece. Overall, 155 of 450 hosted migrants and two of 46 employees were infected (attack rates: 34.4% and 4.3%, respectively). The mean age of infected migrants was 24.9 years (3 days-68 years). In addition, 177 community contacts were tested negative. Cases were cohorted in separate rooms from people tested negative. Surfaces were cleaned and disinfected daily. The implementation of measures for the containment of the outbreak was challenging due to language barriers and lack of space for cohorting. At that time, there was no official recommendation to the general population regarding the use of masks or other personal protective equipment. Extensive testing of vulnerable populations and building trust in order to report symptoms and comply with the recommendations are essential.

Innate Variability in Physiological and Omics Aspects of the Beta Thalassemia Trait-Specific Donor Variation Effects.

The broad spectrum of beta-thalassemia (ßThal) mutations may result in mild reduction (ß ++), severe reduction (ß +) or complete absence (ß 0) of beta-globin synthesis. ßThal heterozygotes eligible for blood donation are "good storers" in terms of red blood cell (RBC) fragility, proteostasis and redox parameters of storage lesion. However, it has not been examined if heterogeneity in genetic backgrounds among ßThal-trait donors affects their RBC storability profile. For this purpose, a paired analysis of physiological and omics parameters was performed in freshly drawn blood and CPD/SAGM-stored RBCs donated by eligible volunteers of ß ++ (N = 4), ß + (N = 9) and ß 0 (N = 2) mutation-based phenotypes. Compared to ß +, ß ++ RBCs were characterized by significantly lower RDW and HbA2 but higher hematocrit, MCV and NADPH levels in vivo. Moreover, they had lower levels of reactive oxygen species and markers of oxidative stress, already from baseline. Interestingly, their lower myosin and arginase membrane levels were accompanied by increased cellular fragility and arginine values. Proteostasis markers (proteasomal activity and/or chaperoning-protein membrane-binding) seem to be also diminished in ß ++ as opposed to the other two phenotypic groups. Overall, despite the low number of samples in the sub-cohorts, it seems that the second level of genetic variability among the group of ßThal-trait donors is reflected not only in the physiological features of RBCs in vivo, but almost equally in their storability profiles. Mutations that only slightly affect the globin chain equilibrium direct RBCs towards phenotypes closer to the average control, at least in terms of fragility indices and proteostatic dynamics.

Association of Preoperative Basal Inflammatory State, Measured by Plasma suPAR Levels, with Intraoperative Sublingual Microvascular Perfusion in Patients Undergoing Major Non-Cardiac Surgery.

It remains unknown whether chronic systemic inflammation is associated with impaired microvascular perfusion during surgery. We evaluated the association between the preoperative basal inflammatory state, measured by plasma soluble urokinase-type plasminogen activator receptor (suPAR) levels, and intraoperative sublingual microcirculatory variables in patients undergoing major non-cardiac surgery. Plasma suPAR levels were determined in 100 non-cardiac surgery patients using the suPARnostic® quick triage lateral flow assay. We assessed sublingual microcirculation before surgical incision and every 30 min during surgery using Sidestream Darkfield (SDF+) imaging and determined the De Backer score, the Consensus Proportion of Perfused Vessels (Consensus PPV), and the Consensus PPV (small). Elevated suPAR levels were associated with lower intraoperative De Backer score, Consensus PPV, and Consensus PPV (small). For each ng mL−1 increase in suPAR, De Backer score, Consensus PPV, and Consensus PPV (small) decreased by 0.7 mm−1, 2.5%, and 2.8%, respectively, compared to baseline. In contrast, CRP was not significantly correlated with De Backer score (r = −0.034, p = 0.36), Consensus PPV (r = −0.014, p = 0.72) or Consensus PPV Small (r = −0.037, p = 0.32). Postoperative De Backer score did not change significantly from baseline (5.95 ± 3.21 vs. 5.89 ± 3.36, p = 0.404), while postoperative Consensus PPV (83.49 ± 11.5 vs. 81.15 ± 11.8, p < 0.001) and Consensus PPV (small) (80.87 ± 13.4 vs. 78.72 ± 13, p < 0.001) decreased significantly from baseline. In conclusion, elevated preoperative suPAR levels were associated with intraoperative impairment of sublingual microvascular perfusion in patients undergoing elective major non-cardiac surgery.

Early and Late-Phase 24 h Responses of Stored Red Blood Cells to Recipient-Mimicking Conditions.

The 24-hour (24 h) post-transfusion survival of donor red blood cells (RBCs) is an important marker of transfusion efficacy. Nonetheless, within that period, donated RBCs may encounter challenges able to evoke rapid stress-responses. The aim of the present study was to assess the effect of exposure to plasma and body temperature upon stored RBCs under recipient-mimicking conditions in vitro from the first hours "post-transfusion" up to 24 h. For this purpose, packed RBCs from seven leukoreduced CPD/SAGM units were reconstituted with plasma of twenty-seven healthy individuals and incubated for 24 h at 37oC. Three units were additionally used to examine stress-responses in 3-hour intervals post mixing with plasma (n = 5) until 24 h. All experiments were performed in shortly-, medium-, and long-stored RBCs. Hemolysis, redox, morphology, membrane protein binding and vesiculation parameters were assessed. Even though spontaneous hemolysis was minimal post-reconstitution, it presented a time-dependent increase. A similar time-course profile was evident for the concentration of procoagulant extracellular vesicles and the osmotic fragility (shortly-stored RBCs). On the contrary, mechanical fragility and reactive oxygen species accumulation were characterized by increases in medium-stored RBCs, evident even from the first hours in the recipient-mimicking environment. Finally, exposure to plasma resulted in rapid improvement of morphology, especially in medium-stored RBCs. Overall, some RBC properties vary significantly during the first 24 h post-mixing, at levels different from both the storage ones and the standard end-of-24 h. Such findings may be useful for understanding the performance of RBCs and their possible clinical effects -especially on susceptible recipients- during the first hours post-transfusion.

Economic crisis in Greece: The invisible enemy of blood donation or not?

INTRODUCTION: Volunteering presupposes having free time and refers to the provision of services without the motivation of material reward, for the benefit of society. In this study, we aimed to provide insight into the impact of economic crisis on blood donors and their motivation to donate blood during that period. STUDY DESIGN AND METHODS: We asked blood donors about their blood donation activity and motivation to donate using a standardized, anonymous questionnaire (n = 3000). Descriptive analysis was performed for the consideration of donor turnout during this economic period. The results were analyzed using the χ2 test and Spearman's correlation coefficient. RESULTS: Regarding gender, 68.2% were males, while 31.8% were females. Most blood donors donated voluntarily (75.8%) and only 24.2% were replacement or family blood donors. The economic crisis has affected the inhabitants of Athens more than the inhabitants of the province (χ2 = 9.910,p = 0.007). The influence of economic crisis on the regular blood donors' quality of life was greater than the non-regular donors (χ2 = 16.227,p < 0.001). According to our results, the economic crisis reduced the quality of life, but it did not affect the frequency of blood donations in a percentage of 87,3%. Not any significant difference was found between employment status, economic crisis and blood donation. CONCLUSION: Although the economic crisis has affected the lives of blood donors, it does not seem to affect the frequency of blood donation. We suggest that blood collection services should consider specialist campaigns that focus on the altruistic motivation of donors during an economic crisis.

Corpuscular Fragility and Metabolic Aspects of Freshly Drawn Beta-Thalassemia Minor RBCs Impact Their Physiology and Performance Post Transfusion: A Triangular Correlation Analysis In Vitro and In Vivo.

The clarification of donor variation effects upon red blood cell (RBC) storage lesion and transfusion efficacy may open new ways for donor-recipient matching optimization. We hereby propose a "triangular" strategy for studying the links comprising the transfusion chain-donor, blood product, recipient-as exemplified in two cohorts of control and beta-thalassemia minor (ßThal+) donors (n = 18 each). It was unraveled that RBC osmotic fragility and caspase-like proteasomal activity can link both donor cohorts to post-storage states. In the case of heterozygotes, the geometry, size and intrinsic low RBC fragility might be lying behind their higher post-storage resistance to lysis and recovery in mice. Moreover, energy-related molecules (e.g., phosphocreatine) and purine metabolism factors (IMP, hypoxanthine) were specifically linked to lower post-storage hemolysis and phosphatidylserine exposure. The latter was also ameliorated by antioxidants, such as urate. Finally, higher proteasomal conservation across the transfusion chain was observed in heterozygotes compared to control donors. The proposed "triangularity model" can be (a) expanded to additional donor/recipient backgrounds, (b) enriched by big data, especially in the post-transfusion state and (c) fuel targeted experiments in order to discover new quality biomarkers and design more personalized transfusion medicine schemes.

Deciphering the Relationship Between Free and Vesicular Hemoglobin in Stored Red Blood Cell Units.

Red blood cells (RBCs) release hemoglobin (Hb)-containing extracellular vesicles (EVs) throughout their lifespan in the circulation, and especially during senescence, by spleen-facilitated vesiculation of their membrane. During ex vivo aging under blood bank conditions, the RBCs lose Hb, both in soluble form and inside EVs that accumulate as a part of storage lesion in the supernatant of the unit. Spontaneous hemolysis and vesiculation are increasingly promoted by the storage duration, but little is known about any physiological linkage between them. In the present study, we measured the levels of total extracellular and EV-enclosed Hb (EV-Hb) in units of whole blood (n = 36) or packed RBCs stored in either CPDA-1 (n = 99) or in CPD-SAGM additive solution (n = 46), in early, middle, and late storage. The spectrophotometry data were subjected to statistical analysis to detect possible correlation(s) between storage hemolysis and EV-Hb, as well as the threshold (if any) that determines the area of this dynamic association. It seems that the percentage of EV-Hb is negatively associated with hemolysis levels from middle storage onward by showing low to moderate correlation profiles in all strategies under investigation. Moreover, 0.17% storage hemolysis was determined as the potential cut-off, above which this inverse correlation is evident in non-leukoreduced CPDA units. Notably, RBC units with hemolysis levels > 0.17% are characterized by higher percentage of nanovesicles (<100 nm) over typical microvesicles (100-400 nm) compared with the lower hemolysis counterparts. Our results suggest an ordered loss of Hb during RBC accelerated aging that might fuel targeted research to elucidate its mechanistic basis.

Beta thalassemia minor is a beneficial determinant of red blood cell storage lesion.

Blood donor genetics and lifestyle affect the quality of red blood cell (RBC) storage. Heterozygotes for beta thalassemia (bThal+) constitute a non-negligible proportion of blood donors in the Mediterranean and other geographical areas. The unique hematological profile of bThal+ could affect the capacity of enduring storage stress, however, the storability of bThal+ RBC is largely unknown. In this study, RBC from 18 bThal+ donors were stored in the cold and profiled for primary (hemolysis) and secondary (phosphatidylserine exposure, potassium leakage, oxidative stress) quality measures, and metabolomics, versus sex- and age-matched controls. The bThal+ units exhibited better levels of storage hemolysis and susceptibility to lysis following osmotic, oxidative and mechanical insults. Moreover, bThal+ RBC had a lower percentage of surface removal signaling, reactive oxygen species and oxidative defects to membrane components at late stages of storage. Lower potassium accumulation and higher uratedependent antioxidant capacity were noted in the bThal+ supernatant. Full metabolomics analyses revealed alterations in purine and arginine pathways at baseline, along with activation of the pentose phosphate pathway and glycolysis upstream to pyruvate kinase in bThal+ RBC. Upon storage, substantial changes were observed in arginine, purine and vitamin B6 metabolism, as well as in the hexosamine pathway. A high degree of glutamate generation in bThal+ RBC was accompanied by low levels of purine oxidation products (IMP, hypoxanthine, allantoin). The bThal mutations impact the metabolism and the susceptibility to hemolysis of stored RBC, suggesting good post-transfusion recovery. However, hemoglobin increment and other clinical outcomes of bThal+ RBC transfusion deserve elucidation by future studies.

Red cell proteasome modulation by storage, redox metabolism and transfusion.

BACKGROUND: Proteasomes are proteolytic complexes with prominent roles in the control of protein homeostasis and cellular viability. However, little is known about the effects of storage and glucose-6-phosphate dehydrogenase deficiency (G6PD-) on the activity and topology of red blood cell (RBC) proteasomes. MATERIALS AND METHODS: We investigated the concentration (by GeLC-MS proteomics analysis and immunoblotting), activity (by using peptide substrates and proteasome inhibitors), and subcellular/extracellular distribution (following cell fractionation and isolation of extracellular vesicles, respectively) of RBC proteasomes in fresh blood and RBCs from control and G6PD- donors following storage in leukoreduced units. RBC proteasome activity was also tested in transfusion-mimicking conditions in vitro. RESULTS: Stored RBCs were characterised by decreased cytosolic proteasome activity compared to fresh RBCs but increased membrane activity and protein concentration levels. Active proteasomes along with other "repair or destroy" proteins are recruited to the membrane during storage. A proportion of them is released in the supernatant in soluble form or inside extracellular vesicles. Significantly increased enzymatic activity and release of proteasomes were observed in G6PD- vs control RBCs. Similar variations were observed in stress protein biomarkers at the G6PD- membrane. The proteasome profile (mainly the caspase-like activity) had significant correlations with the G6PD- metabolome and quality markers of the RBC units. The storage-induced modifications in the proteasome activities were only partly restored in transfusion-mimicking conditions. DISCUSSION: Storage conditions and G6PD deficiency affect (individually and in synergy) the abundance, distribution, activity, and release of RBC proteasomes. The partial irreversibility of these effects in transfusion-mimicking conditions demands further investigation of their clinical impact on transfusion outcomes.

The Post-Storage Performance of RBCs from Beta-Thalassemia Trait Donors Is Related to Their Storability Profile.

Blood donors with beta-thalassemia traits (ßThal+) have proven to be good "storers", since their stored RBCs are resistant to lysis and resilient against oxidative/proteotoxic stress. To examine the performance of these RBCs post-storage, stored ßThal+ and control RBCs were reconstituted in plasma donated from transfusion-dependent beta-thalassemic patients and healthy controls, and incubated for 24 h at body temperature. Several physiological parameters, including hemolysis, were evaluated. Moreover, labeled fresh/stored RBCs from the two groups were transfused in mice to assess 24 h recovery. All hemolysis metrics were better in the group of heterozygotes and distinguished them against controls in the plasma environment. The reconstituted ßThal+ samples also presented higher proteasome activity and fewer procoagulant extracellular vesicles. Transfusion to mice demonstrated that ßThal+ RBCs present a marginal trend for higher recovery, regardless of the recipient's immune background and the RBC storage age. According to correlation analysis, several of these advantageous post-storage characteristics are related to storage phenotypes, like the cytoskeleton composition, low cellular fragility, and enhanced membrane proteostasis that characterize stored ßThal+ RBCs. Overall, it seems that the intrinsic physiology of ßThal+ RBCs benefits them in conditions mimicking a recipient environment, and in the circulation of animal models; findings that warrant validation in clinical trials.

Red Blood Cell Proteasome in Beta-Thalassemia Trait: Topology of Activity and Networking in Blood Bank Conditions.

Proteasomes are multi-catalytic complexes with important roles in protein control. Their activity in stored red blood cells (RBCs) is affected by both storage time and the donor's characteristics. However, apart from their abundancy in the membrane proteome, not much is known about their topology, activity, and networking during the storage of RBCs from beta-thalassemia trait donors (ßThal+). For this purpose, RBC units from fourteen ßThal+ donors were fractionated and studied for proteasome activity distribution and interactome through fluorometric and correlation analyses against units of sex- and aged-matched controls. In all the samples examined, we observed a time-dependent translocation and/or activation of the proteasome in the membrane and a tight connection of activity with the oxidative burden of cells. Proteasomes were more active in the ßThal+ membranes and supernatants, while the early storage networking of 20S core particles and activities showed a higher degree of connectivity with chaperones, calpains, and peroxiredoxins, which were nonetheless present in all interactomes. Moreover, the ßThal+ interactomes were specially enriched in kinases, metabolic enzymes, and proteins differentially expressed in ßThal+ membrane, including arginase-1, piezo-1, and phospholipid scramblase. Overall, it seems that ßThal+ erythrocytes maintain a considerable "proteo-vigilance" during storage, which is closely connected to their distinct antioxidant dynamics and membrane protein profile.

Osmotic hemolysis is a donor-specific feature of red blood cells under various storage conditions and genetic backgrounds.

BACKGROUND: Transfusion research has recently focused on the discovery of red blood cell (RBC) storage capacity biomarkers and the elucidation of donor variation effects. This shift of focus can further strengthen personalization of transfusion therapy, by revealing probable links between donor biology, RBC storage lesion profile, and posttransfusion performance. STUDY DESIGN AND METHODS: We performed a paired correlation analysis of osmotic fragility in freshly drawn RBCs and during cold storage in different preservative solutions at weekly intervals until unit's expiration date (n = 231), or following 24 h reconstitution in allogeneic plasma (n = 32) from healthy controls or transfusion-dependent beta-thalassemia patients. RESULTS: We observed exceptional correlation profiles (r > 0.700, p < 10-5 in most cases) of RBC osmotic fragility in the ensemble of samples, as well as in subgroups characterized by distinct genetic backgrounds (sex, beta-thalassemia traits, glucose-6-phosphate dehydrogenase deficiency) and storage strategies (additive solutions, whole blood, RBC concentrates). The mean corpuscular fragility (MCF) of fresh and stored RBCs at each storage time significantly correlated with the MCF of stored RBCs measured at all subsequent time points of the storage period (e.g., MCF values of storage day 21 correlated with those of storage days 28, 35 and 42). A similar correlation profile was also observed between the osmotic hemolysis of fresh/stored RBCs before and following in vitro reconstitution in plasma from healthy controls or beta-thalassemia patients. CONCLUSION: Our findings highlighted the potential of osmotic fragility to serve as a donor-signature on RBCs at every step of any individual transfusion chain (donor, blood product, and probably, recipient).