P5 Regional Variations in the Micromechanical and Biochemical Properties of the Ovine Aorta

Abstract

Background

It is important to understand regional variations in the mechanical and biochemical properties of the aorta to better predict and treat diseases. Although previous studies have been explored regional differences in the structure and biomechanical properties of the aorta, little is known about how these properties vary across its entire length [1, 2].

Objectives

To map the micromechanical and biochemical properties of the ovine aorta from the aortic root to the celiac artery region.

Methods

Fresh ovine aortas (n = 3) were split into nine sections, separated by 2 cm intervals between the aortic root and the celiac artery region. For each section, three biopsies were cut out using a 5 mm biopsy punch (a total of 81 biopsies). An oscillatory nanoindentation method was used to determine the micromechanical properties of the tissue [3]. 16 indents were made per biopsy. The shear storage (G’), the shear loss modulus (G”) were determined [3]. Subsequently, the same samples were used to determine elastin, collagen and glycosaminoglycan (GAG) levels using established biochemical assays.

Results

Overall, there was a significant correlation between an increase in G’ and collagen (P = 0.01) with distance from the aortic root whilst elastin (P = 0.05) and GAG (P = 0.05) levels were significantly decreased.

Conclusions

Our study is the first to comprehensively map the mechanical and biochemical properties across the entire aorta. There was a progressive increase in mechanical properties from the proximal to the distal region, along with an increase in collagen and a decrease in elastin content.