Blood pressure-induced physiological strain variability modulates wall structure and function in aorta rings.

Area of Science:

• Vascular biology
• Mechanobiology
• Biophysics

Background:

• Vascular smooth muscle cells (VSMCs) adapt to mechanical stimuli.
• Physiological blood pressure variability involves cycle-by-cycle strain changes.
• Monotonous stretch (MS) reduces aortic contractility compared to variable stretch (VS).

Purpose of the Study:

• To investigate the effects of VS and MS on aortic wall stiffness and extracellular matrix.
• To explore the role of mitochondrial energy production and cytoskeletal organization in VS-driven mechanotransduction.

Main Methods:

• Reanalysis of existing data for wall stiffness.
• Histologic analysis of aortic wall structure.
• Inhibitor studies on mitochondrial function and cytoskeletal organization.
• Immunohistochemical quantification of β-actin reorganization.

Main Results:

• Aortic stiffness remained unchanged under both MS and VS over 4 hours.
• Nonlinearity in mechanical behavior was more pronounced after MS.
• Mitochondrial energy production and cytoskeletal organization were implicated in VS mechanotransduction.
• β-actin reorganization correlated with contractile forces.
• MS induced greater elastin and collagen reorganization than VS, compensating for reduced contractility.

Conclusions:

• Muscle tone, regulated by stretch variability, is crucial for maintaining aortic structural and mechanical homeostasis.
• Findings have implications for vascular conditions associated with altered blood pressure variability.