Mechanical factors direct mouse aortic remodelling during early maturation.

Area of Science:

• Cardiovascular Biology
• Biomedical Engineering
• Vascular Mechanics

Background:

• Genetic mutations affecting arterial elastic fibers are linked to various diseases.
• Reduced elastin (Eln+/-) mice exhibit compensatory cardiovascular adaptations.
• Fibulin-5 deficiency (Fbln5-/-) in adult mice leads to disorganized elastic fibers, reduced arterial compliance, and hypertension.

Purpose of the Study:

• To investigate the mechanical behavior of the aorta in Fbln5-/- mice during early maturation.
• To determine if compensatory mechanisms are present during elastic fiber assembly in Fbln5-/- mice.
• To understand how collagen compensates for defective elastic fibers in the developing aorta.

Main Methods:

• Mechanical testing of the aorta in Fbln5-/- mice during maturation.
• Analysis of circumferential stretch, stress, and modulus.
• Constitutive modeling to assess elastin and collagen contributions to aortic mechanics.

Main Results:

• Physiologic circumferential stretch, stress, and modulus in Fbln5-/- aorta were maintained near wild-type levels during maturation.
• Constitutive modeling indicated decreased elastin contribution and increased collagen contribution to total stress.
• These findings suggest a compensatory role for collagen in maintaining aortic mechanics despite defective elastic fibers.

Conclusions:

• Collagen structure and mechanics compensate for defective elastic fibers in the maturing aorta of Fbln5-/- mice.
• This compensation helps meet the mechanical requirements of the aorta during development.
• Understanding these mechanisms may provide insights into arterial remodeling in human elastinopathies.