Multimodal Structural Analysis of the Human Aorta: From Valve to Bifurcation

Area of Science:

• Biomedical Engineering
• Vascular Biology
• Histology

Background:

• The arterial wall's structural integrity is maintained by collagen and elastin.
• Understanding regional variations in arterial composition is crucial for vascular health.
• Previous studies have not fully characterized microstructure changes from the aorta to iliac arteries.

Purpose of the Study:

• To quantify the relative proportions of collagen and elastin in the human arterial wall.
• To analyze collagen microstructure variations from the aortic root to the external iliac artery.

Main Methods:

• Post-mortem arterial tissue samples from 16 sites in 14 individuals were analyzed.
• Collagen and elastin content were determined using image analysis of stained sections.
• Scanning electron microscopy quantified collagen fiber diameter and segment length.

Main Results:

• Collagen and elastin percentages were similar in the aortic root to suprarenal aorta.
• Distally, from the suprarenal aorta to iliac arteries, collagen percentage increased while elastin decreased.
• Mean collagen fiber diameter and segment length were significantly larger in the external iliac artery compared to the ascending and abdominal aorta.

Conclusions:

• The aorta and iliac arteries exhibit significant structural non-uniformity.
• A distal increase in collagen and decrease in elastin occurs along the aorta.
• The external iliac artery possesses larger collagen fibers and segments than more proximal aortic regions.