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Background This pilot trial focused on feasibility and safety to provide preliminary data to evaluate the hemostatic potential of cold-stored platelets (2° to 6°C) compared with standard room temperature–stored platelets (20° to 24°C) in adult patients undergoing complex cardiothoracic surgery. This study aimed to assess feasibility and to provide information for future pivotal trials. Methods A single center two-stage exploratory pilot study was performed on adult patients undergoing elective or semiurgent complex cardiothoracic surgery. In stage I, a two-armed randomized trial, platelets stored up to 7 days in the cold were compared with those stored at room temperature. In the subsequent single-arm stage II, cold storage time was extended to 8 to 14 days. The primary outcome was clinical effect measured by chest drain output. Secondary outcomes were platelet function measured by multiple electrode impedance aggregometry, total blood usage, immediate and long-term (28 days) adverse events, length of stay in intensive care, and mortality. Results In stage I, the median chest drain output was 720 ml (quartiles 485 to 1,170, n = 25) in patients transfused with room temperature–stored platelets and 645 ml (quartiles 460 to 800, n = 25) in patients transfused with cold-stored platelets. No significant difference was observed. The difference in medians between the room temperature– and cold-stored up to 7 days arm was 75 ml (95% CI, −220, 425). In stage II, the median chest drain output was 690 ml (500 to 1,880, n = 15). The difference in medians between the room temperature arm and the nonconcurrent cold-stored 8 to 14 days arm was 30 ml (95% CI, −1,040, 355). Platelet aggregation in vitro increased after transfusion in both the room temperature– and cold-stored platelet study arms. Total blood usage, number of adverse events, length of stay in intensive care, and mortality were comparable among patients receiving cold-stored and room temperature–stored platelets. Conclusions This pilot trial supports the feasibility of platelets stored cold for up to 14 days and provides critical guidance for future pivotal trials in high-risk cardiothoracic bleeding patients. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New

Background Human platelet lysate (HPL) is emerging as the preferred xeno-free supplement for the expansion of mesenchymal stromal cells (MSCs) for bone tissue engineering (BTE) applications. Due to a growing demand, the need for standardization and scaling-up of HPL has been highlighted. However, the optimal storage time of the source material, i.e., outdated platelet concentrates (PCs), remains to be determined. The present study aimed to determine the optimal storage time of PCs in terms of the cytokine content and biological efficacy of HPL. Methods Donor-matched bone marrow (BMSCs) and adipose-derived MSCs (ASCs) expanded in HPL or fetal bovine serum (FBS) were characterized based on in vitro proliferation, immunophenotype, and multi-lineage differentiation. Osteogenic differentiation was assessed at early (gene expression), intermediate [alkaline phosphatase (ALP) activity], and terminal stages (mineralization). Using a multiplex immunoassay, the cytokine contents of HPLs produced from PCs stored for 1–9 months were screened and a preliminary threshold of 4 months was identified. Next, HPLs were produced from PCs stored for controlled durations of 0, 1, 2, 3, and 4 months, and their efficacy was compared in terms of cytokine content and BMSCs’ proliferation and osteogenic differentiation. Results BMSCs and ASCs in both HPL and FBS demonstrated a characteristic immunophenotype and multi-lineage differentiation; osteogenic differentiation of BMSCs and ASCs was significantly enhanced in HPL vs. FBS. Multiplex network analysis of HPL revealed several interacting growth factors, chemokines, and inflammatory cytokines. Notably, stem cell growth factor (SCGF) was detected in high concentrations. A majority of cytokines were elevated in HPLs produced from PCs stored for ≤ 4 months vs. > 4 months. However, no further differences in PC storage times between 0 and 4 months were identified in terms of HPLs’ cytokine content or their effects on the proliferation, ALP activity, and mineralization of BMSCs from multiple donors. Conclusions MSCs expanded in HPL demonstrate enhanced osteogenic differentiation, albeit with considerable donor variation. HPLs produced from outdated PCs stored for up to 4 months efficiently supported the proliferation and osteogenic differentiation of MSCs. These findings may facilitate the standardization and scaling-up of HPL from outdated PCs for BTE applications.

Background Some jurisdictions require leukoreduction of cellular blood components. The only whole blood collection set with a platelet-saving filter uses citrate-phosphate-dextrose (CPD) as storage solution. Substituting CPD with citrate-phosphate-dextrose-adenine (CPDA-1) increases shelf life from 21 to 35 days. This would simplify prehospital and rural resupply and reduce wastage. We investigated in vitro quality and hemostatic properties of CPDA-1 whole blood leukoreduced with a platelet-saving filter. Study design and methods CPDA-1 whole blood was leukoreduced using a platelet-saving filter and stored 35 days. EDQM requirements, hematology, metabolic parameters, thromboelastography, light transmission aggregometry, fibrinogen, factor VIII, and interleukin-6 were measured on Days 0, 1, 14, 21, and 35 and compared to non-leukoreduced blood. Results All units met EDQM requirements. Leukoreduction yielded residual white blood cell count 0.8% was observed. Factor VIII was higher on Day 35 in the leukoreduced group, 37.9 (95% CI: 26.0, 49.8) versus 13.8 (9.4, 18.2) IU/dL. In both groups, aggregation was significantly reduced by Day 14. Thromboelastography showed remaining platelet activity on Day 35, MA 46.9 (42.1, 51.7) in the leukoreduced and 44.3 (39.6, 49.0) mm in the non-leukoreduced group. Fibrinogen was within reference ranges at Day 35 (>2 g/dL). Interleukin-6 was not detectable. Conclusion Leukoreducing CPDA-1 whole blood with a platelet-saving filter did not compromise hemostatic properties. We encourage development of a single bag CPDA-1 whole blood collection set with in-line platelet-saving filter.

Background Cold storage of platelets may extend shelf life compared to room temperature storage. This study aimed to investigate in vitro platelet quality and function in cold-stored and delayed-cold-stored nonagitated apheresis platelets in platelet additive solution during storage for 21 days. Study design and methods Ten double apheresis platelet concentrates in 37% plasma/63% PAS-IIIM were split into two groups; nonagitated 2 to 6°C storage (CSPs) and delayed cold storage (DCSPs) with 7 days agitated storage at 20-24°C followed by nonagitated cold storage for 14 additional days. Platelet count, metabolism, viscoelastic properties, and aggregation ability were measured on Days 1, 7, 14, and 21. Results All platelet units, both CSPs and DCSPs, complied with the EU guidelines throughout storage for 21 days. Swirling was not detectable after cold storage. Cold storage improved platelet function; however, DCSP on Day 7 showed poorer results compared to CSP. Cold storage slowed down metabolism, with lower lactate and higher glucose concentrations in the CSP compared to the DCSP throughout storage for 21 days. Conclusion Cold storage of platelets improved platelet function in in vitro assays, even though delayed cold storage on Day 7 showed poorer results compared to continuous cold storage. This difference could be explained by accelerated metabolism and higher glucose consumption during the period of room temperature storage. Cold storage and delayed cold storage could ease inventory management. Further studies investigating the in vitro and clinical effects of cold-stored and delayed-cold-stored platelets are encouraged.

Background Damage control resuscitation principles advocate the use of blood to treat traumatic hemorrhage. Hemorrhage is a leading cause of preventable death on the battlefield, but making blood components available far forward presents logistical challenges due to shelf life and storage requirements. Whole blood simplifies logistics and enables collection in the field but can cause leukocyte-related transfusion reactions. A field-adapted leukoreduction system must be fast and safe, and storage of whole blood should preserve hemostatic function. Methods Blood was collected using Imuflex WB-SP and leukoreduced at 0, 150, or 300 mm Hg. Additional bags were stored at 4°C for 21 days unagitated, mixed daily, agitated or head-over-heel rotated, at 22°C for 3 days, or 32°C for 2 hours. Hematology, coagulation, CD62P/CD42b, thromboelastography (TEG)/thromboelastometry (ROTEM), and Multiplate was performed. Results Filtration time was 35 ± 1, 14 ± 0, and 9 ± 0 minutes at 0, 150, and 300 mm Hg, respectively. One of 10 units at 150 mm Hg and 4 of 11 at 300 mm Hg had residual whole blood cells greater than 5.0 × 10 per unit. One of 11 at 300 mm Hg had platelet recovery of less than 80%. Hemolysis was less than 0.2%. Filtration decreased thromboelastography/thromboelastometry and Multiplate aggregation response. Stored at 4°C, α and MA/MCF moderately decreased regardless of mixing. Significant loss of aggregation response and increased CD62P expression was seen by Day 10. By Day 3, storage at 22°C caused loss of most aggregation. Two-hour storage at 32°C did not significantly affect hemostatic capacity. Conclusion Forced filtration reduced leukoreduction time, but increased residual whole blood cells reduced hemostatic function. Aggregation response deteriorated early in storage, while viscoelastic assays decreased more gradually. Mixing showed no benefits. Level of evidence Diagnostic study, level IV.

Epac1 (Exchange protein directly activated by cAMP 1) limits fluid loss from the circulation by tightening the endothelial barrier. We show here that Epac1−/− mice, but not Epac2−/− mice, have prolonged bleeding time, suggesting that Epac1 may limit fluid loss also by restraining bleeding. The Epac1−/− mice had deficient in vitro secondary hemostasis. Quantitative comprehensive proteomics analysis revealed that Epac1−/− mouse platelets (thrombocytes) had unbalanced expression of key components of the glycoprotein Ib-IX-V (GPIb-IX-V) complex, with decrease of GP1bβ and no change of GP1bα. This complex is critical for platelet adhesion under arterial shear conditions. Furthermore, Epac1−/− mice have reduced levels of plasma coagulation factors and fibrinogen, increased size of circulating platelets, increased megakaryocytes (the GP1bβ level was decreased also in Epac1−/− bone marrow) and higher abundance of reticulated platelets. Viscoelastic measurement of clotting function revealed Epac1−/− mice with a dysfunction in the clotting process, which corresponds to reduced plasma levels of coagulation factors like factor XIII and fibrinogen. We propose that the observed platelet phenotype is due to deficient Epac1 activity during megakaryopoiesis and thrombopoiesis, and that the defects in blood clotting for Epac1−/− is connected to secondary hemostasis.

BACKGROUND Increasing numbers of emergency medical service agencies and hospitals are developing the capability to administer blood products to patients with hemorrhagic shock. Cold‐stored whole blood (WB) is the only single product available to prehospital providers who aim to deliver a balanced resuscitation strategy. However, there are no data on the safety and in vitro characteristics of prehospital stored WB. This study aimed to describe the effects on in vitro quality of storing WB at remote helicopter bases in thermal insulating containers. STUDY DESIGN AND METHODS We conducted a two‐armed single‐center study. Twenty units (test) were stored in airtight thermal insulating containers, and 20 units (controls) were stored according to routine procedures in the Haukeland University Hospital Blood Bank. Storage conditions were continuously monitored during emergency medical services missions and throughout remote and blood bank storage. Hematologic and metabolic variables, viscoelastic properties, and platelet (PLT) aggregation were measured on Days 1, 8, 14, and 21. RESULTS Storage conditions complied with the EU guidelines throughout remote and in‐hospital storage for 21 days. There were no significant differences in PLT aggregation, viscoelastic properties, and hematology variables between the two groups. Minor significantly lower pH, glucose, and base excess and higher lactate were observed after storage in airtight containers. CONCLUSION Forward cold storage of WB is safe and complies with EU standards. No difference is observed in hemostatic properties. Minor differences in metabolic variables may be related to the anaerobic conditions within the thermal box. publishedVersion

This is the pre-peer reviewed version of the following article: Wendelbo, Ø., Opheim, E.N., Hervig, T., Lunde, T.H.F., Bruserud, Ø., Mollnes, T.E. & Reikvam, H. (2018). Cytokine profiling and post-transfusion haemoglobin increment in patients with haematological diseases. Vox Sanguinis, 113, 657-668, which has been published in final form at https://doi.org/10.1111/vox.12703. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. Background and Objectives: In a previous pilot study, we demonstrated significantly lower haemoglobin (Hb) increment after red‐blood‐cell (RBC) transfusions in febrile patients compared to patients without fever. The aim of this study was to examine associations between inflammatory mediators and post‐transfusion haemoglobin increment in patients with haematological diseases. Materials and Methods: Twenty‐seven patients (eight women, 19 men), median age 56 years receiving RBC transfusion, were included in the study. Hb increment per unit transfused was corrected for estimated patient blood volume and the amount of Hb transfused. A wide spectrum of inflammatory mediators was determined by multiplex technology. Association between post‐transfusion haemoglobin increment, plasma inflammatory mediators and patient characteristics was analysed using a mixed linear regression model. Results: Febrile patients had significantly lower corrected Hb increment, significantly increased values of IL‐6, IL‐8, IL‐10 and G‐CSF, significantly reduced levels of CCL5 and CXCL10, and significantly higher pretransfusion levels of CRP. There was a significant association between pretransfusion CRP levels and corrected Hb increment for the whole patient cohort, but not within each of the two groups. Results demonstrated an association between haemoglobin increment, fever and inflammatory mediators. Febrile patients had a significantly lower corrected Hb increment compared to nonfebrile patients, when adjusting for mediators. When fever was kept constant, a significant negative association between haemoglobin increment and the proinflammatory mediators IL‐6 and IL‐8 was observed. Conclusion: Both fever and the inflammatory mediators IL‐6 and IL‐8 were negatively associated with post‐transfusion haemoglobin increment.

The 2009 pandemic H1N1 (A(H1N1)pdm09) virus had a highly divergent hemagglutinin (HA) compared to pre-2009 seasonal H1N1 strains. Most peoples were immunologically naive to the A(H1N1)pdm09, although hospital workers were exposed early in the pandemic before pandemic vaccines became available. Here, we evaluated how pre-existing antibodies influence the induction of cross-functional HA stalk antibodies following A(H1N1)pdm09 vaccination. Fifty-six healthcare workers vaccinated with AS03 adjuvanted A(H1N1)pdm09 vaccine were chosen by their pre-vaccination priming status (primed HI titers ≥ 40 or unprimed < 40). We analyzed the HA head- and stalk-specific serum IgG subclasses at pre- and 21 days post-vaccination. We also assessed the functionality of the HA stalk-specific antibodies to neutralize virus and mediate antibody dependent cellular cytotoxicity (ADCC). Primed individuals had higher pre-existing HA head- and stalk-specific IgG1, as well as higher ADCC functionality of stalk antibodies. However, following vaccination with the adjuvanted pandemic vaccine, only the quantity of HA head specific IgG1 antibodies were significantly higher than in unprimed individuals. The priming status did not impact upon the cross-reactive HA stalk specific IgG antibodies or their ability to neutralize virus or induce ADCC post-vaccination. In conclusion, a single dose of AS03 adjuvanted pandemic vaccine elicited similar levels of functional antibodies in naive and primed individuals. These findings are important for understanding the immunological factors that impact or modulate pandemic vaccine responses in humans.