Browsing by Author "Chumpuchanaphai S."

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    Neutrophil extracellular traps induced by activated platelets as a cause of neutrophil–platelet aggregation in β-thalassaemia/haemoglobin E patients
    (2026-01-01) Thubthed R.; Praneetponkang R.; Sittipaisankul P.; Thiengtavor C.; Chumpuchanaphai S.; Paiboonsukwong K.; Fucharoen S.; Pattanapanyasat K.; Vadolas J.; Smith D.R.; Svasti S.; Chaichompoo P.; Thubthed R.; Mahidol University
    The hypercoagulable state is a major contributor to thromboembolic events and mortality in β-thalassaemia. The mechanisms underlying platelet-induced neutrophil activation leading to immunothrombosis remain poorly understood. Three-dimensional confocal microscopy demonstrated that platelets induced neutrophil extracellular trap (NET) formation through P-selectin- or high mobility group box 1 protein (HMGB1)-mediated binding to P-selectin glycoprotein ligand-1 (PSGL-1) or receptor for advanced glycation end products (RAGE), respectively, on neutrophils. Molecular signalling pathways involved in NETs—focusing on mitogen-activated protein kinase kinase (MAPKK) or mitogen-activated protein kinase kinase 1/2 (MAP2K) (MEK)/extracellular signal–regulated kinase (ERK), reactive oxygen species (ROS), ofnicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex 2 (NOX2), myeloperoxidase (MPO) and peptidylarginine deiminase 4 (PAD4)—were investigated in neutrophils from β-thalassaemia/haemoglobin E (HbE) patients (splenectomy and non-splenectomy) and from normal subjects by priming neutrophils with specific inhibitors before treatment with either platelets, recombinant P-selectin or disulphide HMGB1. In splenectomised patients, neutrophils primed with U0126, but not an ERK inhibitor, exhibited reduced web-like NETs and cell aggregation, associated with antioxidant effects. In non-splenectomised patients and normal subjects, P-selectin activated MEK/ERK, NOX2, MPO and PAD4 pathways, promoting web-like NETs and cell aggregation. HMGB1 activated neutrophils via MEK/ERK, NOX2, MPO and PAD4 pathways, in all groups, resulting in NETs without aggregation-associated NET morphology. These findings indicate that splenectomy alters P-selectin and HMGB1 expression on platelets, leading to altered signalling dynamics in neutrophils and promoting neutrophil–platelet aggregation. ROS pathway could be a key regulator of NET-driven thrombosis in splenectomised β-thalassaemia/HbE disease and highlight its potential as a therapeutic target.
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    Prostaglandin I2 Inhibit Platelet Activation and Preserve Ultrastructure during Platelet Isolation by Centrifugation
    (2024-01-01) Unchaleevilawan P.; Praneetponkang R.; Panta C.; Chumpuchanaphai S.; Paiboonsukwong K.; Worawichawong S.; Svasti S.; Chaichompoo P.; Unchaleevilawan P.; Mahidol University
    Background: Platelets play role in hemostasis, therefore, either decreasing or increasing in platelet structure/function affects hemodynamic disorders. Platelet structural abnormalities and platelet dysfunction can cause bleeding disorder. In contrast, an increasing in α-granules and mitochondria, increased circulating reticulated platelets and platelet hyperfunction which led to hypercoagulable state that contribute to thrombosis. Therefore, ultrastructural and platelet function analysis are required for diagnosis, determining molecular abnormalities, and exploring novel therapeutic approaches. Method: Platelet rich plasma (PRP) was collected from citrateanticoagulated blood samples from healthy donors (n = 3), then being centrifuged at 150×g for 10 min. Platelets were then isolated from PRP with or without prostaglandin I2 (PGI2, 2.5 - 10 μg/mL) by centrifugation at 25°C, either at low-speed (400×g for 20 min) or high-speed (14, 000×g for 2 min). Flow cytometric analysis was used to determine platelet activation (CD41a+CD62P+). Transmission electron microscope was used to determine ultrastructure of platelets. Results: Platelet activation was not significantly difference between whole blood (3±1%) and PRP (5±2%). Notably, centrifugation of PRP increased platelet activation at both lowspeed (51±23%) and highspeed (66±21%). At high-speed centrifugation, PRP treated with PGI2 at 10 μg/mL was 1.5- to 5-fold reduced in platelet activation compared to untreated PRP. However, PGI2 had no effect in preventing platelet activation by low-speed centrifugation. Ultrastructure analysis of platelets is isolated by highspeed centrifugation with 10 μg/mL PGI2 present with preserved platelet ultrastructure contain α-granules, dense granules, mitochondria and open canalicular system. Conclusion: Therefore, 10 μg/mL PGI2 was suitable for inhibiting platelet activation during highspeed centrifugation.