Flow cytometric detection of circulating platelet-derived microparticles in healthy adult horses.

The research article focuses on the development of a flow cytometric assay for the quantification of platelet-derived microparticles (PMPs) in the blood and plasma of healthy adult horses. The study discovered that there were significantly more PMPs in fresh whole blood than in fresh platelet-poor plasma (PPP). The assay could be performed on fresh PPP or whole blood or samples stored in either refrigerated or room temperature for up to 24 hours.

Development of the Flow Cytometric Assay

• The researchers assumed the task of formulating a flow cytometric assay capable of quantifying PMPs in equine whole blood and plasma.
• The method involved preparing platelet-poor plasma (PPP) from fresh whole blood through low-speed centrifugation done twice at 2,500 × g.
• Samples from the fresh whole blood and the PPP were extracted and stored at two different temperatures, 4° and 24°C for 24 hours.

Characterization of Platelet-derived Microparticles

• PMPs were characterized in the collected samples on two measurements – the forward scatter threshold (log forward scatter < 10(1)) and the labeling with annexin V (indicating externalized phosphatidylserine) and CD61 (a constitutive platelet receptor).
• A fluorescent bead-calibrated flow cytometric assay was pursued to establish microparticle counts.
• In addition to this, platelet counts, prothrombin time, and activated partial thromboplastin time were gauged in the fresh samples.

Results and Conclusions

• Results from the study showed notably more PMPs in fresh whole blood (median, 3,062 PMPs/μL; range, 954 to 13,531 PMPs/μL) compared to in fresh PPP (median, 247 PMPs/μL; range, 104 to 918 PMPs/μL).
• Neither of the storage temperatures had any significant effect on PMP counts for whole blood or PPP.
• No correlation was marked between PMP counts and platelet counts in fresh whole blood or PPP or between PMP counts and clotting times in fresh PPP.
• The study concluded that the PMP protocol they created could efficiently quantify PMPs in equine blood and plasma via flow cytometry.
• The quantification could be undertaken for fresh PPP or whole blood or samples that have been stored at room temperature or refrigerated for 24 hours.