Fluid flow increases membrane permeability to merocyanine 540 in human endothelial cells

Francois Berthiaume, John A. Frangos

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


Fluid shear stress is a ubiquitous stimulus of mammalian cell metabolism; however, its signal transduction pathway is unknown. We hypothesized that shear stress may alter some physical properties of the cell membrane. Using primary human umbilical vein endothelial cells (HUVECs), we investigated the effects of shear on the cell membrane by monitoring flow-induced changes in the uptake of the amphipath merocyanine 540 (MC540). Under static conditions, MC540 was rapidly internalized by HUVECs at 37°C, and so was the membrane impermeant dye lucifer yellow, suggesting that the MC540 uptake was partly due to endocytosis. However, exposure to steady flow for 5 min at 37°C induced an increase in MC540 uptake while that of lucifer yellow was unchanged, suggesting that the flow-induced increase in MC540 uptake was not endocytosis-related. The increase in MC540 uptake was significant for levels of steady shear of 6 dyne/cm2 and above. Pulsatile flow was more stimulatory than steady flow at 2 dyne/cm2, but no significant difference between the two was seen at higher shear stress levels. We conclude that fluid shear stress enhanced the uptake of MC540 by a mechanism other than endocytosis, suggesting an increase in plasma membrane permeability during exposure of the cells to shear stress.

Original languageEnglish (US)
Pages (from-to)209-218
Number of pages10
JournalBBA - Biomembranes
Issue number1
StatePublished - Apr 20 1994
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Cell Biology


  • Endothelial cell
  • Flow
  • Membrane permeability
  • Merocyanine 540
  • Shear stress


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