Fluid shear attenuates endothelial pseudopodia formation into the capillary lumen

Area of Science:

• Physiology
• Cell Biology
• Biophysics

Background:

• Endothelial cells exhibit morphological changes, including pseudopodia projection into capillaries.
• These projections impact blood flow resistance and are influenced by hemodynamic forces.

Purpose of the Study:

• Investigate in vivo hemodynamic conditions controlling endothelial pseudopod formation.
• Examine mechanotransduction mechanisms in capillary endothelial cells.

Main Methods:

• Studied rat skeletal muscle capillaries under controlled perfusion.
• Observed and quantified endothelial pseudopodia using electron microscopy and differential interference contrast microscopy.
• Assessed formation under physiological, stasis, and reperfusion flow conditions.

Main Results:

• Physiological fluid flow inhibits pseudopod projection.
• Near-zero flow increased pseudopod incidence from 5% to 55%.
• Red blood cells prevented pseudopod formation; about half retracted upon flow restoration.

Conclusions:

• A mechanism controlled by hemodynamic fluid stress regulates endothelial cytoplasmic projections.
• Understanding pseudopodia may be crucial for cardiovascular disease research, particularly capillary obstruction.