A flow cytometric method for characterization of circulating cell-derived microparticles in plasma

Area of Science:

• Biomedical Engineering
• Flow Cytometry
• Hematology

Background:

• Circulating microparticles (MPs) are crucial biomarkers, but many are smaller than the detection limit of standard flow cytometers.
• Previous flow cytometry instruments had limited sensitivity for analyzing the majority of microparticles.

Purpose of the Study:

• To establish a novel flow cytometry method for analyzing microparticle (MP) subpopulations.
• To leverage a new generation BD FACSAria™ III digital flow cytometer for enhanced MP detection.

Main Methods:

• Plasma samples from 24 healthy individuals were analyzed for MP subpopulations.
• MPs were identified by size (<1.0-µm), Lactadherin-FITC labeling, and cell-specific markers.
• The sensitivity and reproducibility of the BD FACSAria™ III were evaluated against a previous-generation instrument.

Main Results:

• The BD FACSAria™ III demonstrated superior sensitivity and a wider MP detection range compared to the FC500.
• Microparticle subpopulations from platelets, monocytes, erythrocytes, and endothelial cells were identified and quantified.
• Phosphatidylserine (PS)-exposing MPs constituted 15.1±5.5% of total MPs, with significantly higher levels observed in men.

Conclusions:

• A robust method for measuring microparticles (MPs) above the detection limit of advanced flow cytometers was successfully established.
• The method allows for the characterization of diverse MP subpopulations in a healthy population.
• Findings indicate potential sex-based differences in PS-exposing MP levels.