Structural and architectural changes during arterial development and the role of hemodynamics

Area of Science:

• Cardiovascular Biology
• Developmental Biology
• Biomedical Engineering

Background:

• Hemodynamics significantly influences arterial tree development and wall structure.
• Arterial intimal proliferation begins in utero, often eccentrically, preceding diffuse thickening.
• Existing theories view intimal thickening as inherent or adaptive to hemodynamic stress, but this overlooks qualitative changes and degenerative aspects.

Purpose of the Study:

• To investigate the underlying mechanisms of arterial intimal proliferation and associated degenerative changes.
• To propose an alternative hypothesis for intimal thickening beyond simple adaptation to hemodynamic stress.

Main Methods:

• Review of existing literature on arterial development, hemodynamics, and structural changes.
• Analysis of qualitative changes in arterial wall structure during development.
• Postulation of a bioengineering fatigue model based on hemodynamic forces.

Main Results:

• Intimal proliferation occurs early in development, even in utero and in lower animals.
• Degenerative changes in the arterial wall are observed in young individuals and progress postnatally.
• Hemodynamic forces, including pulse wave stretching and flow vibrations, may induce bioengineering fatigue.

Conclusions:

• Arterial intimal proliferation is postulated as a compensatory reparative response to bioengineering fatigue.
• This fatigue results from longitudinal stretching and circumferential distension caused by pulse waves and flow vibrations.
• The proposed mechanism offers an alternative explanation for intimal thickening and degenerative changes in the arterial wall.