Microparticle analysis of clinical plasma samples using acoustic trapping

• DOI: 10.1096/fasebj.30.1_supplement.lb147
• Publication Date: 2023-11-26T16:24:46Z
• Authors: Paulina Bryl‐Gorecka; Ramasri Sathanoori; Olof Gidlöf; Siv Svensson; Mikael Evander; Thomas Laurell; Bjorn Olde; David Erlinge

ObjectiveEndothelial dysfunction, inflammation and platelet activation are conditions that predispose for development of cardiovascular disease. These are also conditions previously shown to trigger release of microparticles (MPs). As isolation of MPs from plasma is time consuming and requires large sample volumes, we decided to develop an alternative method based on acoustic trapping. Acoustic trapping is a non‐contact method where sound waves are used to retain particles in a microfluidic channel (Figure 1). Exciting a capillary with a piezoelectric transducer that creates a local acoustic standing wave field will enable trapping and clustering of particles in this zone. Submicron particles can subsequently be trapped on the larger particles by inter‐particle acoustic forces, so called “seed trapping”. As a test of the method we analyzed the change in endothelial MPs (EMPs) release that was stimulated by physical excersise in healthy controls and subjects with coronary artery disease.Methods Patient and control samples: 8 patients with history of coronary artery disease and 5 healthy subjects underwent physical exercise (cycling). Blood samples were collected into EDTA tubes before and 1h after exercise. The samples were centrifuged at 1,600 × g for 15 minutes and then stored at −80°C. Isolation of MPs: Plasma samples were subjected to centrifugation (2 times 1600 × g, 15 min, 4°C) in order to obtain platelet‐free plasma. 25 ul of sample was aspirated and the microparticles were trapped and subsequently eluted in 100 ul PBS. Staining of CD62E (E‐selectin)+ EMPs: The microparticles were stained with 3 ul of PE‐conjugated anti‐CD62E antibody for 45 min at room temperature, in the dark with constant shaking, followed by FACS analysis using a BD Accuri C6 cytometer. ResultsCD62E+ MPs ranged from 25 to 77 and 20 to 62 events/ul for patients and controls respectively. A decrease in numbers of CD62E+ MPs was observed 1 h after exercise for both patient and control samples. This decrease was present in both groups, but it was more pronounced in the patients.ConclusionsAcoustic trapping technique may be used for isolation of MPs, including EMPs, from human plasma. The presented results indicate an anti‐inflammatory effect of physical exercise on the endothelium.Support or Funding InformationSwedish foundation for strategic research