Structure of the interendothelial cell cleft

Area of Science:

• Biophysics
• Cell Biology
• Vascular Biology

Background:

• The interendothelial cell cleft is a narrow gap connecting blood vessel lumen and subendothelial space.
• A key characteristic of this cleft is its consistent width.

Purpose of the Study:

• To propose a mechanism for maintaining the constant width of the interendothelial cell cleft.
• To investigate the role of electrostatic repulsions and inter-wall posts in cleft width regulation.

Main Methods:

• Theoretical modeling and detailed calculations to demonstrate the proposed mechanism.
• Review of recent ultrastructural evidence supporting the existence of single chain links.

Main Results:

• Electrostatic repulsions and a system of posts effectively maintain cleft width.
• Single macromolecular chain links, particularly when charged, function as stiff springs of fixed length.
• The proposed posts do not significantly increase hydrodynamic resistance.

Conclusions:

• The constant width of the interendothelial cell cleft is maintained by electrostatic forces and a unique system of posts.
• Similar post structures are proposed to support subendothelial layers.
• Single chain links provide a plausible ultrastructural basis for this mechanism.