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Background and Objectives Materials and Methods Results Conclusion Quantifying the contribution of individual coagulation factors to haemostasis may aid our understanding of the haemostatic function in patients with rare coagulation deficiencies (RCDs) and the exploration of suitable treatments.Reconstituted blood prepared from specific coagulation factor‐deficient plasma (factor [F]II; prothrombin, FV, FVII, FVIII, FIX, FX, FXI or FXII) and red blood cell/platelet products were used to simulate the whole blood of patients with RCD. We prepared in vitro treatment models for patients with prothrombin deficiency using coagulation factor agents and fresh frozen plasma. Haemostatic function was measured using a microchip flow chamber system at 600 s−1.The haemostatic function was low, especially in blood samples reconstituted with prothrombin‐ and FX‐deficient plasma. In a plasma transfusion model of prothrombin deficiency, haemostatic function recovered after 10% replacement with normal plasma and reached a plateau at ≧60% replacement. A treatment model of prothrombin deficiency with prothrombin complex concentrates revealed dose‐dependent therapeutic effects in the range of 0–50 IU/kg.Microchip flow chamber system‐based quantification of haemostatic function using reconstituted blood could predict haemostasis and therapeutic effects of treatments in patients with prothrombin deficiency. [ABSTRACT FROM AUTHOR]

Background and Objectives Materials and Methods Results Conclusion The total thrombus‐formation analysis system (T‐TAS) can quantitatively analyse the contribution of platelets to haemostasis using reconstituted blood samples. However, it is unsuitable in cases with low platelet counts. We introduced a haemodilution (HD) chip with a shallow chamber depth, adapted to low platelet counts and high shear conditions (1500 s−1).Blood samples were prepared by mixing red blood cell products, standard human plasma and platelet products; the final platelet count was 50 × 103/μL. Aggregation tests were performed by using the aggregation inducers collagen, adenosine diphosphate (ADP) and ristocetin. Samples with 2‐, 4‐ and 9‐day‐old platelet products (N = 10) were evaluated.The HD chip enabled the stable analysis of the haemostatic function of all samples at a platelet count of 50 × 103/μL. Haemostatic function was correlated with ADP aggregation (time to 10 kPa [T10]: r = −0.53; area under the curve for 30 min: r = 0.40) and storage period (T10: r = 0.44).The HD chip‐mounted T‐TAS can stably analyse haemostatic function under low platelet counts and high shear conditions; this approach is expected to serve as a bridge to in vivo haemostatic tests with experimental animals. [ABSTRACT FROM AUTHOR]

Background and Objectives: Platelet concentrates suspended in a platelet additive solution (PAS‐PC) are associated with a reduction in allergic response and are suitable for preparing pathogen‐inactivated PC. We aimed to develop an efficient platform for the dual preparation of PAS‐PC and platelet‐poor plasma. Materials and Methods: PAS‐PC was prepared in six steps by using a hollow‐fibre system based on cross‐flow filtration: priming, loading PC, loading PAS, collection of filtered liquid (flow‐through) and collection of platelets by washing with PAS followed by washing with air. In this study, the efficacy of platelet and plasma protein recovery and characteristics of recovered PAS‐PC and flow‐through plasma were analysed in detail. Results: Recoveries of platelet in PAS‐PC and plasma protein in the flow‐through were 95.4% ± 3.7% and 61.6% ± 5.0%, respectively. The residual plasma protein in PAS‐PC was 34.1% ± 2.8%. Although the expression level of CD62P, a platelet activation marker, in recovered platelets was approximately 1.2‐fold of that in original platelets, swirling patterns were well retained, and aggregation in PAS‐PC was not visible. Agonist‐induced aggregabilities, platelet morphology and hypotonic shock recovery were conserved. The patterns of plasma protein and lipoprotein in the flow‐through were comparable with those in the original PCs. The multimeric pattern analysis of VWF remained unaltered. Conclusion: We propose a highly efficient preparation system that enables the simultaneous production of PAS‐PC and platelet‐poor plasma. It also achieves a high recovery of functionally well‐retained platelets with very low activation. [ABSTRACT FROM AUTHOR]

Background and objectives: Although HLA‐eliminated platelets can facilitate transfusions to patients possessing HLA antibodies, no such products are currently available commercially perhaps because the platelet collection rate is not yet economically viable. We have improved this process' efficiency by employing a hollow‐fibre system at the last step of the production process after an acid and a reaction buffer have been washed out conventionally by centrifugation. Materials and methods: HLA‐eliminated platelets were prepared via four distinct steps: chilled on ice, treated with an acid solution, diluted and finally washed using the hollow‐fibre system. The efficiency of this platelet recovery process was determined. The resulting products' platelet characteristics, including a capacity for HLA expression, were evaluated in vitro and compared in detail to their corresponding originals. Results: The average efficiency of platelet recovery was 91%. Although the expression levels of CD62P, a molecular marker for platelet activation, were approximately threefold higher on new platelets than on the original platelets, their HLA expression levels were lower. The phagocytosis assay, with monoclonal antibodies and cognate HLA antibody‐containing sera, suggested that HLA‐ABC molecules on the cell surface were sufficiently removed. The platelet functions, including the agonist‐induced aggregability and adherence/aggregability of the collagen‐coated plates under certain conditions, were conserved and not significantly different from the original ones. Conclusion: We propose a novel preparation system for producing HLA‐eliminated platelets without centrifugation, which ensures a highly efficient, and therefore, much more economical method of platelet recovery that also retains their key functionality. [ABSTRACT FROM AUTHOR]

Background and Objectives: Currently, the quality of platelet (PLT) products is evaluated using a series of in vitro tests, which only analyse PLTs as an inspection material. However, it would be ideal to assess the physiological functions of PLTs under conditions similar to the sequential blood haemostatic process. In this study, we attempted to establish an in vitro system where the thrombogenicity of PLT products was evaluated in the presence of red blood cells (RBCs) and plasma using a microchamber under constant shear stress (600/s). Materials and Methods: Blood samples were reconstituted by mixing PLT products, standard human plasma (SHP) and standard RBCs. Each component was serially diluted keeping the other two components fixed. The samples were applied onto a flow chamber system (Total Thrombus‐formation Analysis System [T‐TAS]), and white thrombus formation (WTF) was assessed under large arterial shear conditions. Results: We observed a good correlation between the PLT numbers in the test samples and WTF. The WTF of samples containing ≦10% SHP was significantly lower than those containing ≧40% SHP, and no difference was observed in WTF among samples containing 40%–100% SHP. WTF significantly declined in the absence of RBCs, whereas no change in WTF was observed in the presence of RBCs, over haematocrit range of 12.5%–50%. Conclusion: The WTF assessed on the T‐TAS using reconstituted blood may serve as a new physiological blood thrombus test to quantitatively determine the quality of PLT products. [ABSTRACT FROM AUTHOR]