Shape change in human platelets: measurement with a channelyzer and visualisation by electron microscopy
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Published on: July 28, 2021
I A Jagroop1, I Clatworthy, J Lewin
1Department of Molecular Pathology and Clinical Biochemistry, Royal Free & University College Medical School (University of London), UK.
Abstract:
The increase in median platelet volume (MPV) that occurs following the addition of various agonists can be recorded by high-resolution channelyzers. However, this increase in MPV may not represent the platelet shape change (PSC), an early phase of platelet activation characterised by the formation of pseudopodia. We therefore compared the MPV after adding various agonists (serotonin, ADP or a thromboxane A2 analogue) with scanning electron micrographs (EM) of the platelets in the same sample. Saline alone did not increase the MPV or alter platelet morphology. In contrast, the selected agonists altered both the MPV and EM. Adrenaline (5.0 mumol/l) alone did not influence either of these indices of platelet activation. However, when a lower concentration of adrenaline (0.2 mumol/l) was added in combination with a dose of serotonin (0.02 mumol/l) that did not affect the MPV on its own, the measured MPV increased significantly and the EM showed pseudopodia formation. Because the channelyzer method is reproducible and suited to serial measurements of the MPV, it may become a useful tool for the investigation of platelet activation.
Insights
Median platelet volume (MPV) changes can indicate platelet activation. This study shows MPV increase and pseudopodia formation, suggesting MPV is a useful tool for investigating platelet activation.
Area of Science:
- Hematology
- Biophysics
Background:
- Median platelet volume (MPV) increases with platelet activation.
- MPV increase may not fully represent early platelet activation, such as platelet shape change (PSC).
Purpose of the Study:
- To compare MPV changes with scanning electron microscopy (SEM) findings of platelet morphology.
- To evaluate MPV as an indicator of early platelet activation.
Main Methods:
- Platelets were treated with agonists (serotonin, ADP, thromboxane A2 analogue, adrenaline).
- MPV was measured using high-resolution channelyzers.
- Platelet morphology was assessed using scanning electron microscopy (SEM).
Main Results:
- Agonists altered both MPV and SEM findings.
- Adrenaline alone did not affect MPV or SEM.
- Combined low-dose adrenaline and serotonin significantly increased MPV and induced pseudopodia formation (PSC).
Conclusions:
- MPV increase correlates with early platelet activation and pseudopodia formation.
- Channelyzer-based MPV measurement is a reproducible method for serial measurements.
- MPV measurement is a valuable tool for investigating platelet activation.
