Analysis of structural changes in normal and aneurismal human aortic tissues using FTIR microscopy

Area of Science:

• Biomedical Engineering
• Biophysics
• Analytical Chemistry

Background:

• Aortic aneurysms are often asymptomatic, with diagnosis relying solely on diameter, not structural composition.
• Current diagnostic methods lack a basis for assessing tissue structure and composition.

Purpose of the Study:

• To explore infrared microspectroscopy for nondestructively probing normal and aneurysmal human aortas.
• To identify spectral differences related to tissue composition between normal and aneurysmal aortas.

Main Methods:

• Acquired infrared spectra from 19 human ascending aortic biopsies (10 normal, 9 aneurysmal).
• Investigated 7-microm thick cryosections with 30-microm spatial resolution.
• Utilized hierarchical cluster analysis for tissue heterogeneity and classification.

Main Results:

• Spectral differences were primarily in regions associated with proteins (elastin, collagen) and proteoglycans.
• 100% classification accuracy was achieved using protein-related spectral ranges.
• Proteoglycan spectral ranges were less effective for discrimination.

Conclusions:

• Infrared microspectroscopy shows potential for differentiating normal and aneurysmal aortas based on spectral analysis.
• Future research will focus on elastin and collagen spectral regions for improved discrimination.
• This technique may offer a new compositional basis for aortic aneurysm diagnosis.