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Updated: Oct 23, 2025
Microfluidics in Assessing Platelet Function
Published on: November 8, 2024
Persistent circulating platelet and endothelial derived microparticle signature may explain on-going
S Koganti1, D Eleftheriou2, R Gurung3
1Citizens Specialty Hospital, Hyderabad, India; UCL Institute of Cardiovascular Science, London, UK.
Aims:
Microparticles (MPs) are submicron vesicles, released from activated, and apoptotic cells. MPs are elevated in the circulation of patients with coronary artery disease (CAD) and have pro-thrombotic potential. However, limited data exists on MP signature over time following an acute coronary event.
Methods & Results:
Circulating total annexin v + (Anv+) MPs of endothelial (EMP), platelet (PMP), monocyte (MMP), neutrophil (NMP) and smooth muscle cell (SMMP) origin were quantified by flow cytometry. 13 patients with acute coronary syndrome (ACS) were prospectively enrolled and 12 patients with stable angina (SA) were included as a comparator group. A panel of MP was measured at baseline, after percutaneous coronary intervention (PCI) and at days 1, 7, 30 and 6 months. Intra & inter group comparison was made between various time points. MP mediated thrombin generation was measured by recording lag phase, velocity index, peak thrombin and endogenous thrombin potential at these time points and compared with healthy controls. The total AnV+ MP levels were similar in ACS and SA groups at baseline, peaked immediately after PCI and were at their lowest on day 1. PMP & EMP levels remained significantly elevated in ACS patients at 6 months when compared to SA. No such difference was noted with NMP, MMP and SMMP. Patients with coronary artery disease showed abnormal thrombograms when compared to controls. Peak thrombin (nano moles) was significantly higher in CAD when compared to controls (254 IQR [226, 239] in ACS, 255 IQR [219, 328] in SA and 132 IQR [57, 252] in controls; p = 0.006). Differences in thrombin generation between ACS and SA were not significant (p = 1). Furthermore, thrombin parameters remained abnormal in ACS & SA patients at 6 months.
Conclusions:
Total MP and individual MP phenotypes were significantly elevated after PCI reflecting endothelial injury. Elevated PMP and EMP levels at 6 months in ACS patients is suggestive of on-going inflammation, endothelial injury and may explain on-going pro-thrombogenicity seen up to 6 months after ACS despite dual antiplatelet therapy.
Insights
Microparticle (MP) levels, particularly platelet-derived MPs (PMP) and endothelial-derived MPs (EMP), remain elevated for six months post-acute coronary syndrome (ACS). This suggests ongoing inflammation and endothelial injury, contributing to persistent pro-thrombotic risk in ACS patients.
Area of Science:
- Cardiovascular Medicine
- Hematology
- Cell Biology
Background:
- Microparticles (MPs) are small vesicles released from cells, implicated in coronary artery disease (CAD) and possessing pro-thrombotic properties.
- Elevated circulating MPs are observed in CAD patients, but their temporal dynamics after an acute coronary event are not well-characterized.
Purpose of the Study:
- To investigate the longitudinal changes in circulating microparticle (MP) levels and their pro-thrombotic potential following an acute coronary syndrome (ACS).
- To compare MP signatures between patients with ACS and stable angina (SA).
Main Methods:
- Quantification of circulating MPs (endothelial, platelet, monocyte, neutrophil, smooth muscle cell origin) using flow cytometry in ACS and SA patients.
- MP levels were measured at baseline, post-percutaneous coronary intervention (PCI), and at 1, 7, 30, and 6 months.
- MP-mediated thrombin generation was assessed by analyzing lag phase, velocity index, peak thrombin, and endogenous thrombin potential.
Main Results:
- Total MP levels peaked immediately after PCI and decreased by day 1, but remained elevated compared to controls up to 6 months.
- Platelet-derived MPs (PMP) and endothelial-derived MPs (EMP) were significantly elevated in ACS patients at 6 months compared to SA patients.
- Patients with CAD (ACS and SA) exhibited abnormal thrombin generation compared to healthy controls, with parameters remaining abnormal at 6 months.
Conclusions:
- PCI significantly increases total MPs and individual phenotypes, indicating endothelial injury.
- Sustained elevation of PMP and EMP in ACS patients at 6 months suggests ongoing inflammation and endothelial damage.
- These findings may explain the persistent pro-thrombotic state observed in ACS patients, even with dual antiplatelet therapy.
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