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1.  In vitro measures of membrane changes reveal differences between red blood cells stored in SAGM and AS-1 additive solutions: a paired study 
Transfusion  2013;54(3):560-568.
Background
Saline-Adenine-Glucose-Mannitol (SAGM) and a variant solution, AS-1 have been used for over 30 years to preserve red blood cells (RBCs). Reputedly these RBC components have similar quality, although no paired study has been reported. To determine whether differences exist, a paired study of SAGM-RBCs and AS-1-RBCs was conducted to identify membrane changes, including microparticle (MP) quantitation and in vitro RBC-endothelial cell (EC) interaction.
Study Design and Methods
Two whole blood packs were pooled-and-split and RBCs prepared (n=6 pairs). One pack was suspended in SAGM and one in AS-1. Samples were collected during 42 days of refrigerated storage. RBC shape/size, glycophorin A (GPA)+ and phosphatidylserine (PS)+ MPs were measured by flow cytometry. RBC adhesion to ECs was determined by an in vitro flow perfusion assay. Routine parameters (pH, hemolysis) were also measured.
Results
Compared to SAGM-RBCs, AS-1-RBCs had lower hemolysis (p<0.04), lower GPA+ MPs (p<0.03) and lower PS+ MPs (p<0.03) from day 14 onwards. AS-1-RBCs had higher (p<0.02) side scatter from day 28 onwards, compared to SAGM-RBCs. SAGM-RBCs were more adherent to ECs at day 28 of storage compared to AS-1 RBCs (p=0.04), but reversed at day 42 (p=0.02). No significant differences in forward scatter or pH were found.
Conclusion
SAGM-RBCs lose more membrane during storage. SAGM-RBCs had increased adherence to ECs at day 28 of storage, while AS-1-RBCs were more adherent at day 42. The effect of these differences on the function and survival of SAGM-RBCs and AS-1-RBCs following transfusion remains to be determined.
doi:10.1111/trf.12344
PMCID: PMC4173075  PMID: 23869602
2.  Serial assessment of biochemical parameters of red cell preparations to evaluate safety for neonatal transfusions 
Background & Objectives:
Neonatologists often prefer fresh blood (<7 days) for neonatal transfusions. The main concerns for stored RBCs are ex vivo storage lesions that undermine red cell functions and may affect metabolic status of neonatal recipients. This study was designed to evaluate serial in vitro changes of biochemical parameters in different RBC preparations during storage to consider for neonatal transfusions even after storage beyond one week.
Methods:
Twenty five units each of whole blood (CPDA-1 RBC, SAGM RBC) were selected for serial biochemical parameter assessment after each fulfilled the quality criteria (volume and haematocrit). These units were tested serially for supernatant potassium, pH, lactate, haemoglobin, glucose and red cell 2,3 diphosphoglycerate (2,3 DPG) up to 21 days of storage.
Results:
Within each group of RBC, rise in mean concentration of potassium, lactate and plasma haemoglobin from day 1 to 21 of storage was significant in CPDA-1 RBC having the highest levels at day 21. From day 3 to 21, SAGM RBC had higher mean pH value than CPDA-1 RBC though this difference was not statistically significant. SAGM RBC had highest mean glucose concentration during storage than other two types of red cell preparations (P<0.005). Within each group, fall in mean 2,3 DPG concentration from day 1 to 7 was significant (P<0.05). A positive correlation existed between mean plasma potassium and haemoglobin in all three types of red cells (r=0.726, 0.419, 0.605 for CPDA-1 RBC, SAGM RBC and whole blood respectively, P<0.005).
Interpretation & Conclusions:
All the three red cell preparations tested revealed biochemical changes within acceptable limits of safety till 21 days of storage. CPDA-1 RBCs had the highest degree of these changes.
PMCID: PMC3102460  PMID: 21245620
Biochemical changes; packed red cells; whole blood
3.  Erythrocyte Concentrates Recovered from Under-Collected Whole Blood: Experimental and Clinical Results 
PLoS ONE  2015;10(2):e0117928.
Background
Although periodic blood shortages are widespread in major Chinese cities, approximately 1x105 U of whole blood are discarded yearly because of under-collection. To reduce the wastage of acid citrate dextrose solution B (ACD-B) anticoagulated under-collected whole blood (UC-WB), this study was performed to elucidate the effect of extracellular pH and holding time on erythrocyte quality. Mannitol-adenine-phosphate (MAP) erythrocyte concentrates (UC-RBCs) were prepared with UC-WB to assess the safety and efficacy of this component.
Methods
The effect of the different extracellular pH levels and storage times on erythrocytes was assessed by fluorescent probes, SDS-PAGE electrophoresis, electron microscopy and spectroscopy. In vitro properties of 34 UC-RBCs that were prepared with UC-WB at different times after collection were analyzed and compared to normal RBCs during 35 days of storage. The results of transfusion with UC-RBCs and the incidence of adverse reactions in 49 patients were determined.
Results
1) Low extracellular pH levels and long storage time induced increases in RBC fluorescence polarization and mean microviscosity, changes in membrane fluidity, band 1, 2 and 3 protein expression, and erythrocyte morphology. 2) During storage for 35 days, difference in between-subjects effects of K+, hemolysis and supernatant erythrocyte membrane protein (EMP) were statistically significant (P = 0.041, 0.007 and 0.002, respectively), while the differences between these parameters in the 4 h group and comparable controls were less significant. 3) Clinical data from 49 patients confirmed that transfusions with UC-RBCs were satisfactory with no adverse reactions.
Conclusion
These results suggest that it is feasible to prepare RBCs with ACD-B anticoagulated UC-WB at a minimum of 66% volume of the labeled collection. It was effective and safe to transfuse the UC-RBCs prepared within 4 h after collection and stored within 7 days. The use of UC-WB would be a welcome addition to limited blood resources in China.
Trial Registration
Chinese Clinical Trial Registry ChiCTR-TRC-13003967
doi:10.1371/journal.pone.0117928
PMCID: PMC4338272  PMID: 25706725
4.  Stored red blood cell susceptibility to in vitro transfusion-associated stress conditions is higher after longer storage and increased by storage in saline-adenine-glucose-mannitol (SAGM) compared to AS-1 solution 
Transfusion  2015;55(9):2197-2206.
Background
Biochemical changes induced in red blood cells (RBCs) during storage may impair their function upon transfusion. Transfusion-associated stresses may further amplify storage lesion effects including increased phosphatidylserine (PS)-exposure at the RBC membrane, microparticle (MP)-release and adhesion to endothelial cells (ECs). RBC stress susceptibility in vitro was investigated in relation to storage time and additive solution.
Study design and methods
Leukocyte-reduced whole blood donations (n=18) were paired, mixed and re-split before separating the RBCs for storage in SAGM or AS-1 solutions. Samples were taken after 3, 21 or 35 days. For oxidative stress treatment RBCs were exposed to 0.5mM tert-butylhydroperoxide. Transfusion-associated stress was simulated by overnight culture at 37 °C with plasma containing inflammatory mediators. PS-exposure and MPs were measured by flow cytometry and adhesion to EC was tested under flow conditions. PS specificity of adhesion was tested by blocking with PS-containing lipid vesicles.
Results
Oxidative stress induced significantly higher PS-exposure and adhesion to ECs in RBCs stored for 35 days compared to 3 days (p<0.04). PS-containing vesicles blocked RBC-EC adhesion. After overnight culture with or without plasma, PS-exposure and EC-adhesion were significantly increased (p<0.05). MP numbers increased with longer RBC storage and after RBC culture with plasma. Culture conditions influenced MP numbers from day 35 RBCs. RBCs stored in SAGM had significantly higher PS-exposure after stress treatment than AS-1 RBCs (p<0.02).
Conclusion
Storage for 35 days significantly increased RBC susceptibility to oxidative and in vitro transfusion-associated stresses and was higher for RBCs stored in SAGM compared to AS-1.
doi:10.1111/trf.13138
PMCID: PMC4573361  PMID: 25968419
Red blood cells; storage lesion; oxidative stress; stress susceptibility; transfusion; phosphatidylserine; adhesion; AS-1; SAGM; microparticles
5.  Metabolomics of AS-1 RBC storage 
Transfusion medicine reviews  2014;28(2):41-55.
Background
Population based investigations suggest that red blood cells (RBCs) are therapeutically effective when collected, processed and stored for up to 42 days under validated conditions prior to transfusion. However, some retrospective clinical studies have shown worse patient outcomes when transfused RBCs have been stored for the longest times. Furthermore, studies of RBC persistence in the circulation after transfusion have suggested that considerable donor-to-donor variability exists, and may affect transfusion efficacy. To understand the limitations of current blood storage technologies and to develop approaches to improve RBC storage and transfusion efficacy, we investigated the global metabolic alterations that occur when RBCs are stored in AS-1 (AS1-RBC).
Methods
Leukoreduced AS1-RBC units prepared from 9 volunteer research donors (12 total donated units) were serially sampled for metabolomics analysis over 42 days of refrigerated storage. Samples were tested by GC/MS and LC/MS/MS, and specific biochemical compounds were identified by comparison to a library of purified standards.
Results
Over three experiments, 185–264 defined metabolites were quantified in stored RBC samples. Kinetic changes in these biochemicals confirmed known alterations in glycolysis and other pathways previously identified in RBCs stored in SAGM (SAGM-RBC). Furthermore, we identified additional alterations not previously seen in SAGM-RBCs (e.g., stable pentose phosphate pathway flux, progressive decreases in oxidized glutathione), and we delineated changes occurring in other metabolic pathways not previously studied (e.g., S-adenosyl methionine cycle). These data are presented in the context of a detailed comparison with previous studies of SAGM-RBCs from human donors and murine AS1-RBCs.
Conclusion
Global metabolic profiling of AS1-RBCs revealed a number of biochemical alterations in stored blood that may affect RBC viability during storage as well as therapeutic effectiveness of stored RBCs in transfusion recipients.
Significance
These results provide future opportunities to more clearly pinpoint the metabolic defects during RBC storage, to identify biomarkers for donor screening and prerelease RBC testing, and to develop improved RBC storage solutions and methodologies.
doi:10.1016/j.tmrv.2014.01.003
PMCID: PMC4004680  PMID: 24636780
Metabolomics; blood storage; AS1-RBCs; transfusion
6.  Oxygen carrying capacity of salvaged blood in patients undergoing off-pump coronary artery bypass grafting surgery: a prospective observational study 
Background
Intraoperative cell salvage (ICS), hereby referred to ‘mechanical red cell salvage’, has been widely used and proven to be an effective way to reduce or avoid the need for allogeneic red blood cells (RBCs)transfusion and its associated complications in surgeries involving major blood loss. However, little is known about the influence of this technique on the functional state of salvaged RBCs. Furthermore, there are no articles that describe the change of free hemoglobin (fHb) in salvage blood during storage, which is a key index of the quality control of salvaged blood. Therefore, in this study, the influence of ICS on the function of salvaged RBCs and the changes of salvaged RBCs during storage were studied with respect to the presence of oxyhemoglobin affinity (recorded as a P50 value) and the level of 2, 3-diphosphoglycerate (2, 3-DPG) and fHb by comparing salvaged RBCs with self-venous RBCs and 2-week-old packed RBCs.
Methods
Fifteen patients undergoing off-pump coronary artery bypass grafting (OPCAB) surgery were enrolled. Blood was collected and processed using a Dideco Electa device. The level of P50, 2, 3-DPG and fHB from salvaged RBCs, venous RBCs and 2-week-old packed RBCs was measured. We also measured the changes of these indicators among salvaged RBCs at 4 h (storage at 21–24 °C) and at 24 h (storage at 1–6 °C).
Results
The P50 value of salvaged RBCs at 0 h (28.77 ± 0.27 mmHg) was significantly higher than the value of venous RBCs (27.07 ± 0.23 mmHg, p = 0.000) and the value of the 2-week-old packed RBCs (16.26 ± 0.62 mmHg, p = 0.000). P50 value did not change obviously at 4 h (p = 0.121) and 24 h (p = 0.384) compared with the value at 0 h. The 2, 3-DPG value of salvaged RBCs at 0 h (17.94 ± 6.91 μmol/g Hb) was significantly higher than the value of venous RBCs (12.73 ± 6.52 mmHg, p = 0.007) and the value of the 2-week-old packed RBCs (2.62 ± 3.13 mmHg, p = 0.000). The level of 2, 3-DPG slightly decreased at 4 h (p = 0.380) and 24 h (p = 0.425) compared with the value at 0 h. Percentage of hemolysis of the salvaged blood at 0 h(0.51 ± 0.27 %) was significantly higher than the level of venous blood (0.07 ± 0.05 %, p = 0.000) and the value of 2-week-old packed RBCs (0.07 ± 0.05 %, p = 0.000), and reached 1.11 ± 0.42 % at 4 h (p = 0.002) and 1.83 ± 0.77 % at 24 h (p = 0.000).
Conclusions
The oxygen transport function of salvaged RBCs at 0 h was not influenced by the cell salvage process and was better than that of the venous RBCs and 2-week-old packed RBCs. At the end of storage, the oxygen transport function of salvaged RBCs did not change obviously, but percentage of hemolysis significantly increased.
doi:10.1186/s13019-015-0330-x
PMCID: PMC4604709  PMID: 26466895
Intraoperative cell salvage; Oxyhemoglobin affinity; 2,3-disphosphoglycerate; Free hemoglobin
7.  Quantification of surgical trauma: comparison of conventional and minimally invasive surgical techniques for pertrochanteric fracture surgery based on markers of inflammation (interleukins) 
Background
Fixation of pertrochanteric fracture is undoubtedly an additional trauma after the fracture itself. In elderly patients, it might have an important impact on the whole organism. In the literature we find various techniques to perform this type of surgery. Up to now, there are no parameters validated for quantification of the invasiveness of a surgical procedure; it is therefore still not demonstrated that any method is less invasive than any other. In an effort to find a way to quantify the invasiveness of a surgical procedure, inflammatory markers were collected in patients undergoing fixation of trochanteric fracture with gliding hip screw [dynamic hip screw (DHS)] using either a conventional (DHS conv) or minimally invasive (DHS MIO) technique.
Method
Two groups of patients were investigated prospectively; 36 of them were treated with conventional DHS technique and 32 with minimally invasive technique. Mean age was 84.7 ± 7.20 and 82.78 ± 7.71 years, respectively. Fracture type was classified according to the AO classification. Interleukin (IL)-6, IL-10, IL-8, and tumor necrosis factor (TNF)-α were measured 1 h before and 1 h after surgery. Student’s t test, chi-square test, and multivariate logistic regression were used for statistical analysis.
Results
Preoperative levels of interleukins showed no significant differences between the two groups. In contrast, the postoperative blood level of IL-6 in patients operated with DHS conv technique (78.41 ± 67.04 pg/ml) was on average higher than in patients operated by DHS MIO technique (39.02 ± 37.36 pg/ml), the mean difference being 39.39 pg/ml [95 % confidence interval (CI) 12.65–66.13 pg/ml; p = 0.0045]. Multivariate logistic regression (backward method with limit of significance 0.05) confirmed that patients operated by conventional technique were significantly more likely to have increased IL-6 after surgery than those operated by MIO technique. IL-8 was measured in only 36 patients (20 for DHS conv, 16 for DHS MIO). No significant differences were found between the two groups; however, there was a drastic decrease postoperatively (p < 0.0001) regardless of the type of surgery performed. IL-10 and TNF-α were tested in all subjects, but did not show significant differences between the two groups. Average length of incision was significantly different (4.61 cm, 95 % CI 3.50–5.71 cm; p < 0.001) between the two groups, being 11.65 ± 2.64 cm for DHS conv and 7.05 ± 1.77 cm for DHS MIO. Similarly, average units of red blood cells (RBCs) transfused [performed for hemoglobin (Hb) <9 g/dl and/or hematocrit (HCT) <27 %] was higher (2.22 ± 0.99) in the DHS conv group compared with the DHS MIO group (1.09 ± 1.20), with average difference of 1.13 (95 % CI 0.59–1.66; p < 0.001).
Conclusions
This attempt to quantify the invasiveness of internal fixation for trochanteric fracture comparing two techniques (DHS conv versus DHS MIO) based on inflammatory markers (IL-6) has given encouraging results. Measurement of systemic inflammatory response to local tissue damage caused by osteosynthesis using IL-6 as marker seems to confirm the lower invasiveness of MIO techniques. These results for trauma cases seem in line with those published for hip prosthesis. Ongoing further studies analyzing the effect of nailing will confirm or invalidate these preliminary results.
doi:10.1007/s10195-012-0199-6
PMCID: PMC3427700  PMID: 22688402
Quantification of surgical trauma; Measuring surgical trauma; Gliding hip screw; Minimally invasive technique; Interleukins
8.  Quantification of surgical trauma: comparison of conventional and minimally invasive surgical techniques for pertrochanteric fracture surgery based on markers of inflammation (interleukins) 
Background
Fixation of pertrochanteric fracture is undoubtedly an additional trauma after the fracture itself. In elderly patients, it might have an important impact on the whole organism. In the literature we find various techniques to perform this type of surgery. Up to now, there are no parameters validated for quantification of the invasiveness of a surgical procedure; it is therefore still not demonstrated that any method is less invasive than any other. In an effort to find a way to quantify the invasiveness of a surgical procedure, inflammatory markers were collected in patients undergoing fixation of trochanteric fracture with gliding hip screw [dynamic hip screw (DHS)] using either a conventional (DHS conv) or minimally invasive (DHS MIO) technique.
Method
Two groups of patients were investigated prospectively; 36 of them were treated with conventional DHS technique and 32 with minimally invasive technique. Mean age was 84.7 ± 7.20 and 82.78 ± 7.71 years, respectively. Fracture type was classified according to the AO classification. Interleukin (IL)-6, IL-10, IL-8, and tumor necrosis factor (TNF)-α were measured 1 h before and 1 h after surgery. Student’s t test, chi-square test, and multivariate logistic regression were used for statistical analysis.
Results
Preoperative levels of interleukins showed no significant differences between the two groups. In contrast, the postoperative blood level of IL-6 in patients operated with DHS conv technique (78.41 ± 67.04 pg/ml) was on average higher than in patients operated by DHS MIO technique (39.02 ± 37.36 pg/ml), the mean difference being 39.39 pg/ml [95 % confidence interval (CI) 12.65–66.13 pg/ml; p = 0.0045]. Multivariate logistic regression (backward method with limit of significance 0.05) confirmed that patients operated by conventional technique were significantly more likely to have increased IL-6 after surgery than those operated by MIO technique. IL-8 was measured in only 36 patients (20 for DHS conv, 16 for DHS MIO). No significant differences were found between the two groups; however, there was a drastic decrease postoperatively (p < 0.0001) regardless of the type of surgery performed. IL-10 and TNF-α were tested in all subjects, but did not show significant differences between the two groups. Average length of incision was significantly different (4.61 cm, 95 % CI 3.50–5.71 cm; p < 0.001) between the two groups, being 11.65 ± 2.64 cm for DHS conv and 7.05 ± 1.77 cm for DHS MIO. Similarly, average units of red blood cells (RBCs) transfused [performed for hemoglobin (Hb) <9 g/dl and/or hematocrit (HCT) <27 %] was higher (2.22 ± 0.99) in the DHS conv group compared with the DHS MIO group (1.09 ± 1.20), with average difference of 1.13 (95 % CI 0.59–1.66; p < 0.001).
Conclusions
This attempt to quantify the invasiveness of internal fixation for trochanteric fracture comparing two techniques (DHS conv versus DHS MIO) based on inflammatory markers (IL-6) has given encouraging results. Measurement of systemic inflammatory response to local tissue damage caused by osteosynthesis using IL-6 as marker seems to confirm the lower invasiveness of MIO techniques. These results for trauma cases seem in line with those published for hip prosthesis. Ongoing further studies analyzing the effect of nailing will confirm or invalidate these preliminary results.
doi:10.1007/s10195-012-0199-6
PMCID: PMC3427700  PMID: 22688402
Quantification of surgical trauma; Measuring surgical trauma; Gliding hip screw; Minimally invasive technique; Interleukins
9.  Sickle Cell Trait Increases Red Blood Cell Storage Hemolysis and Post-Transfusion Clearance in Mice 
EBioMedicine  2016;11:239-248.
Background
Transfusion of blood at the limits of approved storage time is associated with lower red blood cell (RBC) post-transfusion recovery and hemolysis, which increases plasma cell-free hemoglobin and iron, proposed to induce endothelial dysfunction and impair host defense. There is noted variability among donors in the intrinsic rate of storage changes and RBC post-transfusion recovery, yet genetic determinants that modulate this process are unclear.
Methods
We explore RBC storage stability and post-transfusion recovery in murine models of allogeneic and xenogeneic transfusion using blood from humanized transgenic sickle cell hemizygous mice (Hbatm1PazHbbtm1TowTg(HBA-HBBs)41Paz/J) and human donors with a common genetic mutation sickle cell trait (HbAS).
Findings
Human and transgenic HbAS RBCs demonstrate accelerated storage time-dependent hemolysis and reduced post-transfusion recovery in mice. The rapid post-transfusion clearance of stored HbAS RBC is unrelated to macrophage-mediated uptake or intravascular hemolysis, but by enhanced sequestration in the spleen, kidney and liver. HbAS RBCs are intrinsically different from HbAA RBCs, with reduced membrane deformability as cells age in cold storage, leading to accelerated clearance of transfused HbAS RBCs by entrapment in organ microcirculation.
Interpretation
The common genetic variant HbAS enhances RBC storage dysfunction and raises provocative questions about the use of HbAS RBCs at the limits of approved storage.
Highlights
•Sickle cell trait (HbAS) RBC exhibit increased resistance to osmotic shock compared to normal (HbAA) RBCs.•HbAS RBC show accelerated storage-related aging and post-transfusion clearance after cold storage compared to HbAA RBC.•Reduced post-transfusion survival of stored HbAS RBCs is not due to intravascular hemolysis but due to tissue sequestration.
In allogeneic transfusions, red blood cells (RBCs) are collected and stored for up to 42 days. Historically, donor RBC genetic background is only considered in the context of major Rh and ABO blood groups. This study shows that donor-specific genetic factors such as sickle cell trait, the benign heterozygote state of sickle cell disease, accelerate storage-related hemolysis and reduces RBC post-transfusion survival in mice. Impaired post-transfusion recovery is due to enhanced sequestration in organ microcirculation. Further studies are warranted to determine an appropriate earlier outdate for HbAS RBC units, particularly in malaria-endemic regions where sickle cell trait prevalence is high.
doi:10.1016/j.ebiom.2016.08.006
PMCID: PMC5049931  PMID: 27523807
Sickle cell trait; Red cell storage; Blood; Post-transfusion survival; Transfusion practice; RBC hemolysis
10.  Adverse events and retention of donors of double red cell units by apheresis 
Blood Transfusion  2016;14(5):391-399.
Background
Safety of double-erythrocyte (2RBC) collection and reasons for ceasing 2RBC donation were retrospectively analysed in the blood donor population of Basel, Switzerland.
Methods
Donors with at least 1 2RBC apheresis were included in the study. Minimal requirements were Hb ≥140 g/L and body weight ≥70 kg; serum ferritin (SF) values were measured routinely, but were not part of the selection criteria. 2RBC collections were performed with ALYX devices at 6-month intervals. Adverse events (AEs) were systematically recorded and classified according to the ISBT EHN 2008 criteria. Data of procedures were retrieved from the ALYX software. Demographics, apheresis data and AEs were analysed with descriptive statistics.
Results
Data of 4,377 2RBC aphereses performed in 793 donors (779 males) between 1st January 2003 and 31st May 2015 were evaluated. Mean donor age at first 2RBC donation was 44 years (standard deviation [SD] 21), median number of donations was 4 (interquartile range [IQR] 8); 32% of the donors underwent a single procedure. There were 161 AEs, mostly local haematomas (55%) and vasovagal reactions (20%); fatigue was reported in 6% of the cases and was more frequent than citrate toxicity. Two severe AEs were observed. The most frequent reasons for abandoning 2RBC donation were low SF levels and donor choice (both 11%), but most donors simply did not reply to invitations (16%). Overall, procedure-related causes (AEs, low SF levels, no time for apheresis, inadequate venous access) were observed in 14% of the cases. At the end of the observation period, 40% of the donors were still active blood donors, but only 20% were donating 2RBC.
Discussion
2RBC donation is overall safe. Donor retention was low over a period of 11 years. An important reason for abandoning 2RBC was the detection of low SF levels. The impact of fatigue on donor retention and the course of iron stores after repeated 6-monthly 2RBC apheresis require further investigation.
doi:10.2450/2016.0237-15
PMCID: PMC5016297  PMID: 27136442
double red blood cell apheresis; adverse events; donor retention
11.  Impaired Red Blood Cell Deformability After Transfusion of Stored Allogeneic Blood but not Autologous Salvaged Blood in Cardiac Surgery Patients 
Anesthesia and analgesia  2014;118(6):1179-1187.
Background
Both cardiopulmonary bypass (CPB) and red blood cell (RBC) storage are associated with detrimental changes in RBC structure and function that may adversely affect tissue oxygen delivery. We tested the hypothesis that in cardiac surgery patients, RBC deformability and aggregation are minimally affected by CPB with autologous salvaged blood alone, but are negatively affected by the addition of stored allogeneic blood.
Methods
In this prospective cohort study, 32 patients undergoing cardiac surgery with CPB were divided into 3 groups by transfusion status: autologous salvaged RBCs alone (Auto; n=12), autologous salvaged RBCs + minimal (<5 units) stored allogeneic RBCs (Auto+Allo min; n=10), and autologous salvaged RBCs + moderate (≥5 units) stored allogeneic RBCs (Auto+Allo mod; n=10). Ektacytometry was used to measure RBC elongation index (deformability) and critical shear stress (aggregation) before, during, and for 3 days after surgery.
Results
In the Auto group, RBC elongation index did not change significantly from the preoperative baseline. In the Auto+Allo min group, mean elongation index decreased from 32.31 ± 0.02 (baseline) to 30.47 ± 0.02 (nadir on postoperative day 1) (P = 0.003, representing a 6% change). In the Auto+Allo mod group, mean elongation index decreased from 32.7 ± 0.02 (baseline) to 28.14 ± 0.01 (nadir on postoperative day 1) (P = 0.0001, representing a 14% change). Deformability then dose-dependently recovered toward baseline over the first 3 postoperative days. Changes in aggregation were unrelated to transfusion (no difference among groups). For the 3 groups combined, mean critical shear stress decreased from 359 ± 174 mPa to 170 ± 141 mPa (P = 0.01, representing a 54% change), with the nadir at the end of surgery, and returned to baseline by postoperative day 1.
Conclusions
In cardiac surgery patients, transfusion with stored allogeneic RBCs, but not autologous salvaged RBCs, is associated with a decrease in RBC cell membrane deformability that is dose-dependent and may persist beyond 3 postoperative days. These findings suggest that autologous salvaged RBCs may be of higher quality than stored RBCs, since the latter are subject to the so-called “storage lesions.”
doi:10.1213/ANE.0000000000000227
PMCID: PMC4041165  PMID: 24806142
12.  The Heritability of Glutathione and Related Metabolites in Stored Red Blood Cells 
Red blood cells (RBCs) collected for transfusion deteriorate during storage. This deterioration is termed the “RBC storage lesion”. There is increasing concern over the safety, therapeutic efficacy, and toxicity of transfusing longer-stored units of blood. The severity of the RBC storage lesion is dependent on storage-time and varies markedly between individuals. Oxidative damage is considered a significant factor in development of the RBC storage lesion. In this study, the variability during storage and heritability of antioxidants and metabolites central to RBC integrity and function were investigated. In a classic twin study, we determined the heritability of glutathione (GSH), glutathione disulfide (GSSG), the status of the GSSG, 2H+/2GSH couple (Ehc) and total glutathione (tGSH) in donated RBCs over 56 days of storage. Intracellular GSH and GSSG concentrations both decrease during storage (median net loss of 0.52 ± 0.63 mM (median ± SD) and 0.032 ± 0.107mM, respectively over 42 days). Taking into account the decline in pH, Ehc became more positive (oxidized) during storage (median net increase of 35 ± 16 mV). In our study population heritability estimates for GSH, GSSG, tGSH, and Ehc measured over 56 days of storage are 79%, 60%, 67%, and, 75% respectively. We conclude that susceptibility of stored RBCs to oxidative injury due to variations in the GSH-redox buffer are highly variable among individual donors and strongly heritable. Identifying the genes that regulate the storage-related changes in this redox buffer could lead to the development of new methods to minimize the RBC storage lesion.
doi:10.1016/j.freeradbiomed.2014.07.040
PMCID: PMC4252477  PMID: 25108189
red blood cells; erythrocyte; glutathione; heritability; storage lesion; twin study; transfusion medicine
13.  Deterioration of red blood cell mechanical properties is reduced in anaerobic storage 
Blood Transfusion  2016;14(1):80-88.
Background
Hypothermic storage of red blood cells (RBCs) results in progressive deterioration of the rheological properties of the cells, which may reduce the efficacy of RBC transfusions. Recent studies have suggested that storing RBC units under anaerobic conditions may reduce this storage-induced deterioration.
Materials and methods
The aim of this study was to compare the rheological properties of conventionally and anaerobically stored RBC and provide a measure of the relationship between oxidative damage to stored RBC and their ability to perfuse microvascular networks. Three different microfluidic devices were used to measure the ability of both types of stored RBC to perfuse artificial microvascular networks. Flow rates of the RBC passing through the entire network (bulk perfusion) and the individual capillaries (capillary perfusion) of the devices were measured on days 2, 21, 42, and 63 of storage.
Results
The bulk perfusion rates for anaerobically stored RBC were significantly higher than for conventionally stored RBCs over the entire duration of storage for all devices (up to 10% on day 42; up to 14% on day 63). Capillary perfusion rates suggested that anaerobically stored RBC units contained significantly fewer non-deformable RBC capable of transiently plugging microfluidic device capillaries. The number of plugging events caused by these non-deformable RBC increased over the 63 days of hypothermic storage by nearly 16- to 21-fold for conventionally stored units, and by only about 3- to 6-fold for anaerobically stored units.
Discussion
The perfusion measurements suggest that anaerobically stored RBC retain a greater ability to perfuse networks of artificial capillaries compared to conventionally (aerobically) stored RBC. It is likely that anaerobic storage confers this positive effect on the bulk mechanical properties of stored RBC by significantly reducing the number of non-deformable cells present in the overall population of relatively well-preserved RBC.
doi:10.2450/2015.0241-15
PMCID: PMC4731343  PMID: 26674833
anaerobic; storage; rheology; microfluidic; deformability
14.  Impaired ATP release from red blood cells promotes their adhesion to endothelial cells: A mechanism of hypoxemia after transfusion 
Critical care medicine  2011;39(11):2478-2486.
Objective
Transfusion of red blood cells (RBCs) has been linked to disappointing clinical outcomes in the critically ill, but specific mechanisms of organ dysfunction after transfusion remain poorly understood. We tested the hypothesis that RBC storage impairs the ability of RBCs to release ATP and that impaired ATP-release was injurious in vivo, in part through increased RBC adhesion.
Design
Prospective, controlled, mechanistic study.
Setting
University research laboratory.
Subjects
Human and mouse blood donors; nude mouse transfusion recipients.
Interventions
Manipulation of ATP release, supplemental ATP, and antibodies to RBC and endothelial adhesion receptors were used in vitro and in vivo to probe the roles of released ATP and adhesion in responses to (transfused) RBCs.
Measurements and main results
The ability of stored RBCs to release ATP declined markedly within 14 days after collection, despite relatively stable levels of ATP within the RBCs. Inhibiting ATP release promoted the adhesion of stored RBCs to endothelial cells in vitro and RBC sequestration in the lungs of transfused mice in vivo. Unlike transfusion of fresh human RBCs, stored-RBC transfusion in mice decreased blood oxygenation and increased extravasation of RBCs into the lung’s alveolar airspaces. Similar findings were seen with transfusion of fresh RBCs treated with the ATP-release inhibitors glibenclamide and carbenoxolone. These findings were prevented by either co-infusion of an ATP analog or pre-transfusion incubation of the RBCs with an antibody against the erythrocyte adhesion receptor LW (Landsteiner-Wiener; ICAM-4).
Conclusions
The normal flow of RBCs in pulmonary microvessels depends in part on the release of anti-adhesive ATP from RBCs, and storage-induced deficiency in ATP release from transfused RBCs may promote or exacerbate microvascular pathophysiology in the lung, in part through increased RBC adhesion.
doi:10.1097/CCM.0b013e318225754f
PMCID: PMC3196852  PMID: 21765360
erythrocyte; oxygenation; acute lung injury; intercellular adhesion molecule-4 (ICAM-4); Landsteiner-Weiner (LW); endothelium; blood storage
15.  Quantification of Cell-Free DNA in Red Blood Cell Units in Different Whole Blood Processing Methods 
Journal of Blood Transfusion  2016;2016:9316385.
Background. Whole blood donations in Canada are processed by either the red cell filtration (RCF) or whole blood filtration (WBF) methods, where leukoreduction is potentially delayed in WBF. Fresh WBF red blood cells (RBCs) have been associated with increased in-hospital mortality after transfusion. Cell-free DNA (cfDNA) is released by neutrophils prior to leukoreduction, degraded during RBC storage, and is associated with adverse patient outcomes. We explored cfDNA levels in RBCs prepared by RCF and WBF and different storage durations. Methods. Equal numbers of fresh (stored ≤14 days) and older RBCs were sampled. cfDNA was quantified by spectrophotometry and PicoGreen. Separate regression models determined the association with processing method and storage duration and their interaction on cfDNA. Results. cfDNA in 120 RBC units (73 RCF, 47 WBF) were measured. Using PicoGreen, WBF units overall had higher cfDNA than RCF units (p = 0.0010); fresh WBF units had higher cfDNA than fresh RCF units (p = 0.0093). Using spectrophotometry, fresh RBC units overall had higher cfDNA than older units (p = 0.0031); fresh WBF RBCs had higher cfDNA than older RCF RBCs (p = 0.024). Conclusion. Higher cfDNA in fresh WBF was observed compared to older RCF blood. Further study is required for association with patient outcomes.
doi:10.1155/2016/9316385
PMCID: PMC5059535  PMID: 27774338
16.  Red blood cell transfusion and increased length of storage are not associated with deep vein thrombosis in medical and surgical critically ill patients: a prospective observational cohort study 
Critical Care  2011;15(6):R263.
Introduction
With prolonged storage times, cell membranes of red blood cells (RBCs) undergo morphologic and biochemical changes, termed 'RBC storage lesions'. Storage lesions may promote inflammation and thrombophilia when transfused. In trauma patients, RBC transfusion was an independent risk factor for deep vein thrombosis (DVT), specifically when RBC units were stored > 21 days or when 5 or more units were transfused. The objective of this study was to determine if RBC transfusions or RBC storage age predicts incident DVT in medical or surgical intensive care unit (ICU) patients.
Methods
Using a database which prospectively enrolled 261 patients over the course of 1 year with an ICU stay of at least 3 days, we analyzed DVT and RBC transfusions using Cox proportional hazards regression. Transfusions were analyzed with 4 thresholds, and storage age using 3 thresholds. DVTs were identified by twice-weekly proximal leg ultrasounds. Multivariable analyses were adjusted for 4 significant DVT predictors in this population (venous thrombosis history, chronic dialysis, platelet transfusion and inotropes).
Results
Of 261 patients, 126 (48.3%) had at least 1 RBC transfusion; 46.8% of those transfused had ≥ 5 units in ICU. Patients receiving RBCs were older (68.8 vs 64.1 years), more likely to be female (47.0 vs 30.7), sicker (APACHEII 26.8 vs 24.4), and more likely to be surgical (21.4 vs 8.9) (P < 0.05). The total number of RBCs per patient was 1-64, mean was 6.3 (SD 7.5), median was 4 (IQR 2,8). In univariate analyses, there was no association between DVT and RBC exposure (1 day earlier, 3 days earlier, 7 days earlier, or ever) or RBC storage (≤ 7 or > 7 days, ≤ 14 or > 14 days, ≤ 21 or > 21 days). Among patients transfused, no multivariable analyses showed that RBC transfusion or storage age predicted DVT. Trends were counter to the hypothesis (e.g., RBC storage for ≤ 7 days suggested a higher DVT risk compared to > 7 days (HR 5.3; 95% CI 1.3-22.1).
Conclusions
We were unable to detect any association between RBC transfusions or prolonged red cell storage and increased risk of DVT in medical or surgical ICU patients. Alternate explanations include a lack of sufficient events or patients' interaction, between patient groups, a mixing of red cell storage times creating differential effects on DVT risk, and unmeasured confounders.
doi:10.1186/cc10526
PMCID: PMC3388665  PMID: 22044745
17.  Red Cell Apheresis with Automated In-Line Filtration 
Summary
Background
The aim of this study was to provide data on concurrent red blood cell (RBC) and platelet (PLT) apheresis with RBC in-line leukoreduction and automated addition of saline-adenine-glucose-mannitol (SAGM) using the new version (V6.0) of Trima Accel®.
Methods
In this two-center paired study, each subject completed a test and a control procedure with an interval of 9 weeks between procedures. In the test arm, single RBC and PLT units were collected on the Trima Accel V6.0 (in-line leukofiltration and automated addition of SAGM). In the control arm, they were collected on Trima Accel V5.1/V5.2 (post-collection leukoreduction, manual SAGM addition). RBC percent hemolysis, potassium concentration and adenosine triphosphate over storage, hemoglobin (Hb) yield, and residual white blood cells (WBC) were determined.
Results
34 subjects successfully completed both test and control procedures. Post-storage hemolysis was similar in both groups, and all values were less than 0.8% for both arms. Residual WBC counts in all RBC units were less than 1 × 106/unit. In-line processed RBC units (V6.0) have a significantly higher volume and more Hb/unit due to filtration recovery improvements. All procedures were well tolerated by the subjects.
Conclusion
In-line filtration and automated addition of storage solution on Trima Accel V6.0 allows collection of ready-to-use RBC units that meet EU requirements.
doi:10.1159/000357984
PMCID: PMC4025052  PMID: 24847185
Red blood cell; Apheresis; In-line filtration; Leukoreduction; Multicomponent collection; Blood storage
18.  Storage of murine red blood cells enhances alloantibody responses to an erythroid-specific model antigen 
Transfusion  2009;50(3):642-648.
BACKGROUND
Red blood cell (RBC) alloimmunization can be a serious complication of blood transfusion, but factors influencing the development of alloantibodies are only partially understood. Within FDA-approved time limits, RBCs are generally transfused without regard to length of storage. However, recent studies have raised concerns that RBCs stored for more than 14 days have altered biologic properties that may affect medical outcomes. To test the hypothesis that storage time alters RBC immunogenicity, we utilized a murine model of RBC storage and alloimmunization.
STUDY DESIGN AND METHODS
Blood from transgenic HOD donor mice, which express a model antigen (hen egg lysozyme [HEL]) specifically on RBCs, was filter leukoreduced and stored for 14 days under conditions similar to those used for human RBCs. Fresh or 14-day-stored RBCs were transfused into wild-type recipients. The stability of the HOD antigen and post-transfusion RBC survival were analyzed by flow cytometry. RBC alloimmunization was monitored by measuring circulating anti-HEL immunoglobulin levels.
RESULTS
Transfusion of 14-day-stored, leukoreduced HOD RBCs resulted in 10- to 100-fold higher levels of anti-HEL alloantibodies as detected by enzyme-linked immunosorbent assay than transfusion of freshly collected, leukoreduced RBCs. RBC expression of the HOD antigen was stable during storage.
CONCLUSIONS
These findings demonstrate that HOD murine RBCs become more immunogenic with storage and generate the rationale for clinical trials to test if the same phenomenon is observed in humans. Length of storage of RBCs may represent a previously unappreciated variable in whether or not a transfusion recipient becomes alloimmunized.
doi:10.1111/j.1537-2995.2009.02481.x
PMCID: PMC3568949  PMID: 19906034
19.  Quantifying morphological heterogeneity: a study of more than 1,000,000 individual stored red blood cells 
Vox sanguinis  2015;109(3):221-230.
Background and Objectives
The morphology of red blood cells (RBCs) deteriorates progressively during hypothermic storage. The degree of deterioration varies between individual cells, resulting in a highly heterogeneous population of cells contained within each RBC unit. Current techniques capable of categorizing the morphology of individual stored RBCs are manual, laborious, error-prone procedures that limit the number of cells that can be studied. Our objective was to create a simple, automated system for high-throughput RBC morphology classification.
Materials and Methods
A simple microfluidic device, designed to enable rapid, consistent acquisition of images of optimally oriented RBCs, was fabricated using soft lithography. A custom image analysis algorithm was developed to categorize the morphology of each individual RBC in the acquired images. The system was used to determine morphology of individual RBCs in several RBC units stored hypothermically for 6–8 weeks.
Results
The system was used to automatically determine the distribution of cell diameter within each morphological class for >1,000,000 individual stored RBCs (speed: >10,000 cells/hour; accuracy: 91.9% low-resolution, 75.3% high-resolution). Diameter mean and standard deviation by morphology class: discocyte 7.80±0.49μm, echinocyte 1 7.61±0.63μm, echinocyte 2 7.02±0.61μm, echinocyte 3 6.47±0.42μm, sphero-echinocyte 6.01±0.26μm, spherocyte 6.02±0.27μm, stomatocyte 1 6.95±0.61μm, stomatocyte 2 7.32 ± 0.47μm.
Conclusion
The automated morphology classification procedure described in this study is significantly simpler, faster and less subjective than conventional manual procedures. The ability to evaluate the morphology of individual RBCs automatically, rapidly and in statistically significant numbers enabled us to perform the most extensive study of stored RBC morphology to date.
doi:10.1111/vox.12277
PMCID: PMC4669964  PMID: 25900518
storage; morphology; microfluidic
20.  The quality of stored umbilical cord and adult-donated whole blood in Mombasa, Kenya 
Transfusion  2009;50(3):611-616.
BACKGROUND
In sub-Saharan Africa umbilical cord blood may be a useful source of blood for transfusion. Before clinical trials, evidence is needed that cord blood donations, which vary greatly in volume, can be collected and stored into a fixed volume of anticoagulant-preservative solution obviating the need for prestorage processing.
STUDY DESIGN AND METHODS
Twenty-four umbilical cord whole blood (UC-WB) donations were collected into 21 mL of CPDA-1 and refrigerated for 35 days. The Kenya Blood Transfusion Service provided 12 adult-donated whole blood (AD-WB) controls. Supernatant hemoglobin (Hb) and potassium were assayed at 7-day intervals.
RESULTS
UC-WB red blood cell hemolysis and potassium loss increased throughout storage but did not differ significantly with cord blood volume. Hemolysis rates did not differ significantly between UC-WB and AD-WB but UC-WB potassium loss was slightly but significantly greater than AD-WB on Days 2, 7, and 14 (p < 0.05). In the AD-WB controls, eight were low volume (<405 mL), two had total Hb of less than 45 g, and two showed hemolysis greater than 0.8% by Day 28.
CONCLUSION
Variable volumes of UC-WB can be stored for 35 days without prestorage processing and further work into its suitability for transfusion to children is justified. The quality of conventional AD-WB is a concern and needs further evaluation.
doi:10.1111/j.1537-2995.2009.02489.x
PMCID: PMC2948540  PMID: 19912583
21.  The quality of stored umbilical cord and adult-donated whole blood in Mombasa, Kenya 
Transfusion  2010;50(3):611-616.
BACKGROUND:
In sub-Saharan Africa umbilical cord blood may be a useful source of blood for transfusion. Before clinical trials, evidence is needed that cord blood donations, which vary greatly in volume, can be collected and stored into a fixed volume of anticoagulant-preservative solution obviating the need for prestorage processing.
STUDY DESIGN AND METHODS:
Twenty-four umbilical cord whole blood (UC-WB) donations were collected into 21 mL of CPDA-1 and refrigerated for 35 days. The Kenya Blood Transfusion Service provided 12 adult-donated whole blood (AD-WB) controls. Supernatant hemoglobin (Hb) and potassium were assayed at 7-day intervals.
RESULTS:
UC-WB red blood cell hemolysis and potassium loss increased throughout storage but did not differ significantly with cord blood volume. Hemolysis rates did not differ significantly between UC-WB and AD-WB but UC-WB potassium loss was slightly but significantly greater than AD-WB on Days 2, 7, and 14 (p < 0.05). In the AD-WB controls, eight were low volume (<405 mL), two had total Hb of less than 45 g, and two showed hemolysis greater than 0.8% by Day 28.
CONCLUSION:
Variable volumes of UC-WB can be stored for 35 days without prestorage processing and further work into its suitability for transfusion to children is justified. The quality of conventional AD-WB is a concern and needs further evaluation.
doi:10.1111/j.1537-2995.2009.02489.x
PMCID: PMC2948540  PMID: 19912583
22.  Red blood cells stored for increasing periods produce progressive impairments in nitric oxide–mediated vasodilation 
Transfusion  2013;53(11):2619-2628.
BACKGROUND
Clinical outcomes in transfused patients may be affected by the duration of blood storage, possibly due to red blood cell (RBC)-mediated disruption of nitric oxide (NO) signaling, a key regulator of vascular tone and blood flow.
STUDY DESIGN AND METHODS
AS-1 RBC units stored up to 42 days were sampled at selected storage times. Samples were added to aortic rings ex vivo, a system where NO-mediated vasodilation could be experimentally controlled.
RESULTS
RBC units showed storage-dependent changes in plasma hemoglobin (Hb), RBC 2,3-diphosphoglycerate acid, and RBC adenosine triphosphate conforming to expected profiles. When freshly collected (Day 0) blood was added to rat aortic rings, methacholine (MCh) stimulated substantial NO-mediated vasodilation. In contrast, MCh produced no vasodilation in the presence of blood stored for 42 days. Surprisingly, the vasoinhibitory effects of stored RBCs were almost totally mediated by RBCs themselves: removal of the supernatant did not attenuate the inhibitory effects, while addition of supernatant alone to the aortic rings only minimally inhibited MCh-stimulated relaxation. Stored RBCs did not inhibit vasodilation by a direct NO donor, demonstrating that the RBC-mediated vasoinhibitory mechanism did not work by NO scavenging.
CONCLUSIONS
These studies have revealed a previously unrecognized vasoinhibitory activity of stored RBCs, which is more potent than the described effects of free Hb and works through a different mechanism that does not involve NO scavenging but may function by reducing endothelial NO production. Through this novel mechanism, transfusion of small volumes of stored blood may be able to disrupt physiologic vasodilatory responses and thereby possibly cause adverse clinical outcomes.
doi:10.1111/trf.12111
PMCID: PMC4140194  PMID: 23480490
23.  Vascular effects of the red cell storage lesion 
Transfusion of red blood cells (RBCs) is often clinically necessary, and life-saving, for anemic patients. RBCs can be stored for up to 42 days between the time of donation and transfusion. For many years, investigators have studied the biochemical changes that occur in RBCs stored prior to transfusion (the RBC “storage lesion”). More recently, clinical studies have suggested that RBC units stored for long periods (often described as > 14–21 days) may mediate adverse effects in the recipient, leading to morbidity and mortality. Unfortunately, these effects are difficult to identify and study because there are no agreed upon mechanisms for these adverse events, and few good assays to study them in individual transfusion recipients.
We have proposed the hypothesis of Insufficient NO Bio-Availability (INOBA) to explain the adverse events associated with transfusion of older RBC units. INOBA postulates that the combination of impaired NO production/increased NO scavenging by stored RBCs together with reduced NO synthesis by dysfunctional endothelial cells collectively reduce NO levels below a critical threshold in vascular beds. In this situation, inappropriate vasoconstriction occurs leading to reduced blood flow and insufficient O2 delivery to end organs. If confirmed, the INOBA hypothesis can lead to improved methods for blood storage and collection, as well as new screening and matching tools for blood donors and transfusion recipients.
doi:10.1182/asheducation-2011.1.475
PMCID: PMC4793719  PMID: 22160077
Red blood cells; transfusion; nitric oxide
24.  Evaluation of Stem Cell-Derived Red Blood Cells as a Transfusion Product Using a Novel Animal Model 
PLoS ONE  2016;11(12):e0166657.
Reliance on volunteer blood donors can lead to transfusion product shortages, and current liquid storage of red blood cells (RBCs) is associated with biochemical changes over time, known as ‘the storage lesion’. Thus, there is a need for alternative sources of transfusable RBCs to supplement conventional blood donations. Extracorporeal production of stem cell-derived RBCs (stemRBCs) is a potential and yet untapped source of fresh, transfusable RBCs. A number of groups have attempted RBC differentiation from CD34+ cells. However, it is still unclear whether these stemRBCs could eventually be effective substitutes for traditional RBCs due to potential differences in oxygen carrying capacity, viability, deformability, and other critical parameters. We have generated ex vivo stemRBCs from primary human cord blood CD34+ cells and compared them to donor-derived RBCs based on a number of in vitro parameters. In vivo, we assessed stemRBC circulation kinetics in an animal model of transfusion and oxygen delivery in a mouse model of exercise performance. Our novel, chronically anemic, SCID mouse model can evaluate the potential of stemRBCs to deliver oxygen to tissues (muscle) under resting and exercise-induced hypoxic conditions. Based on our data, stem cell-derived RBCs have a similar biochemical profile compared to donor-derived RBCs. While certain key differences remain between donor-derived RBCs and stemRBCs, the ability of stemRBCs to deliver oxygen in a living organism provides support for further development as a transfusion product.
doi:10.1371/journal.pone.0166657
PMCID: PMC5154495  PMID: 27959920
25.  Impact of Transfusion of Autologous 7 versus 42 day old AS-3 Red Blood Cells on Tissue Oxygenation and the Microcirculation in Healthy Volunteers 
Transfusion  2012;52(11):2459-2464.
Background
Stored RBCs accumulate biochemical and biophysical changes. Maximum storage duration is based on acceptable in vitro characteristics and 24-hour survival, but not RBC function. Relatively little is known about the impact of RBC-storage duration on oxygenation and the microcirculation.
Study Design and Methods
Eight healthy subjects donated a double RBC apheresis, which were prestorage leukocyte-reduced, and processed in AS-3. Subjects were transfused one unit of RBCs at 7- and 42-days following blood collection. Measurements of percent (%) tissue oxygenation in the thenar eminence muscle (StO2) and brain (SctO2) were recorded with FDA-cleared non-invasive devices. Sublingual microvascular blood flow (MFI) was quantified prior to and after RBC transfusion using a video microscope. Raw electronic data for all measurements were analyzed by a blinded observer at a core laboratory.
Results
The only pre-versus-posttransfusion change observed in measurements of SctO2, StO2, or MFI was a very small increase in SctO2, from 70.4 to 71.8 (means, p=0.032) at 7 days. There was no significant difference in the amount of pre-post change at 7 days versus 42 days for any of the measures.
Conclusion
Transfusion of one unit of 42-day stored RBCs to healthy subjects has no overt detrimental effect on tissue oxygenation or the microcirculation assessed by clinically available monitors.
doi:10.1111/j.1537-2995.2012.03615.x
PMCID: PMC3387324  PMID: 22452273
transfusion; packed red blood cells (RBCs); tissue oxygenation; microvascular blood flow; near infrared spectroscopy (NIRS); microcirculatory flow index (MFI); age of blood

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