We present a microfluidic device for separating platelet-rich plasma (PRP) from whole blood, addressing key limitations in current sedimentation-based technologies. Unlike existing methods that rely on a single sedimentation trench-limiting plasma yield and processing speed-our device incorporates a novel multi-trench design, allowing the processing of 1 mL of whole blood in 40 minutes, yielding ∼250 μL of PRP with at least a 2-fold increase in platelet concentration. The device is fabricated using a CO2 laser cutter on acrylic layers and bonded with a pressure-sensitive adhesives, offering a cost-effective and simple alternative to more complex manufacturing processes. To ensure reliable PRP separation and minimize bubble formation, we applied a hydrophilic coating at the trench bottoms. We analyzed three trench geometries to optimize PRP yield and quality. Flow simulations optimized shear rates to improve sedimentation. Our approach effectively removes red and white blood cells with purities of 98% and 96%, respectively, only 8.2% of the total platelets were activated post-processing, compared to 31% with conventional centrifugation. This combination of a novel multi-trench layout, simplicity, cost-efficiency, and effective platelet preservation enables a low-cost device for obtaining high-quality PRP for clinical research and therapy.

Detecting occult cancer in patients with unprovoked venous thromboembolism (VTE) remains a significant challenge. Our objective was to investigate the potential predictive role of coagulation-related biomarkers in the diagnosis of occult malignancies.
We conducted a nested case-control study with a 1-year prospective cohort of 214 patients with unprovoked VTE, with a focus on identifying occult cancer. At the time of VTE diagnosis, we measured various biomarkers, including soluble P-selectin (sP-selectin), dimerized plasmin fragment D (D-dimer), platelets, leukocytes, hemoglobin, total extracellular vesicles (EVs), EVs expressing tissue factor on their surface (TF+EVs), and EVs expressing P-selectin on their surface (Psel+EVs) in all participants.
We observed statistically significant increased levels of sP-selectin (P = .015) in patients with occult cancer. Despite an increase in Psel+EVs, TF+EVs, D-dimer, and platelets within this group, however, no significant differences were found. When sP-selectin exceeded 62 ng/mL and D-dimer surpassed 10,000 µg/L, the diagnosis of occult cancer demonstrated a specificity of up to 91% (95% CI, 79.9%-96.7%).
The combination of sP-selectin and D-dimer can be a valuable biomarker in detecting occult cancer in patients with unprovoked VTE. Further research is necessary to ascertain whether easily measurable biomarkers such as sP-selectin and D-dimer can effectively distinguish between patients who have VTE with and without hidden malignancies.
© American Society for Clinical Pathology, 2024.

Somatic mutants of calreticulin (CRT) drive myeloproliferative neoplasms (MPNs) via binding to the thrombopoietin receptor (MPL) and aberrant activation of the JAK/STAT pathway. Compared with healthy donors, platelets from MPN patients with CRT mutations display low cell surface MPL. Co-expression of MPL with an MPN-linked CRT mutant (CRT Del52 ) reduces cell surface MPL expression, indicating the involvement of induced protein degradation, a better understanding of which could lead to new therapies. We show that lysosomal degradation is relevant to the turnover of both CRT Del52 and MPL. Drug-mediated activation of lysosomal degradation reduces CRT Del52 and MPL expression, with parallel inhibition of CRT Del52 -induced cell proliferation and stem cell colony formation. Thus, reduced surface MPL, a marker of platelets from MPN patients with CRT mutations, results from mutant CRT-induced lysosomal degradation of MPL. Drug-induced activation of lysosomal degradation compromises the pathogenic effects of CRT Del52 , which can be further exploited for therapeutic interventions.

Growing evidence supports a central role of NADPH oxidases (NOXs) in the regulation of platelets, which are circulating cells involved in both hemostasis and thrombosis. Here, the use of Nox1-/- and Nox1+/+ mice as experimental models of human responses demonstrated a critical role of NOX1 in collagen-dependent platelet activation and pathological arterial thrombosis, as tested in vivo by carotid occlusion assays. In contrast, NOX1 does not affect platelet responses to thrombin and normal hemostasis, as assayed in tail bleeding experiments. Therefore, as NOX1 inhibitors are likely to have antiplatelet effects without associated bleeding risks, the NOX1-selective inhibitor 2-acetylphenothiazine (2APT) and a series of its derivatives generated to increase inhibitory potency and drug bioavailability were tested. Among the 2APT derivatives, 1-(10H-phenothiazin-2-yl)vinyl tert-butyl carbonate (2APT-D6) was selected for its high potency. Both 2APT and 2APT-D6 inhibited collagen-dependent platelet aggregation, adhesion, thrombus formation, superoxide anion generation, and surface activation marker expression, while responses to thrombin or adhesion to fibrinogen were not affected. In vivo administration of 2APT or 2APT-D6 led to the inhibition of mouse platelet aggregation, oxygen radical output, and thrombus formation, and carotid occlusion, while tail hemostasis was unaffected. Differently to in vitro experiments, 2APT-D6 and 2APT displayed similar potency in vivo. In summary, NOX1 inhibition with 2APT or its derivative 2APT-D6 is a viable strategy to control collagen-induced platelet activation and reduce thrombosis without deleterious effects on hemostasis. These compounds should, therefore, be considered for the development of novel antiplatelet drugs to fight cardiovascular diseases in humans.
© 2020 The Authors. The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology.

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.
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.
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.
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.
© 2020 The Authors. Transfusion published by Wiley Periodicals, Inc. on behalf of AABB.