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Updated: Jul 3, 2026
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Platelet Adhesion and Aggregation Under Flow using Microfluidic Flow Cells
Published on: October 27, 2009
Physiological shear flow enhances pinocytosis in human platelets
Masataka Inoue1, Kasumi Sagawa2, Nobuo Watanabe3
1SIT Research Laboratories, Shibaura Institute of Technology, Saitama, Japan. inoue.masataka.w2@shibaura-it.ac.jp.
Scientific Reports
|July 1, 2026
Summary
Physiological shear rates enhance platelet pinocytosis, a fluid uptake process, via calcium signaling, independent of typical platelet activation. This suggests shear-induced pinocytosis could be leveraged for drug delivery.
Area of Science:
- Hematology
- Cell Biology
- Biophysics
Background:
- Pinocytosis is a poorly understood platelet function.
- The impact of blood flow shear on platelet pinocytosis is unclear.
Purpose of the Study:
- To investigate the effect of physiological shear rates on human platelet pinocytosis.
- To elucidate the role of calcium signaling and plasma factors in shear-modulated pinocytosis.
Main Methods:
- Rotational viscometry combined with flow cytometry.
- Quantification of pinocytosis using pHrodo dextran.
- Measurement of intracellular calcium using Fluo-4.
Main Results:
- Physiological shear rates (500-1500 s⁻¹) enhanced platelet pinocytosis and intracellular calcium levels.
- Shear-induced pinocytosis and calcium elevation were dependent on calcium signaling.
- Shear did not induce canonical platelet activation markers (e.g., integrin αIIbβ3 activation, P-selectin expression).
- Plasma-free conditions enhanced pinocytosis independently of shear and calcium.
Conclusions:
- Physiological shear promotes calcium-dependent platelet pinocytosis via activation-independent pathways.
- Plasma components regulate platelet pinocytosis.
- Shear modulation of pinocytosis offers potential for platelet-based drug delivery systems.
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