Correlations between transmural mechanical and morphological properties in porcine thoracic descending aorta

Determination of correlations between transmural mechanical and morphological properties of aorta would provide a quantitative baseline for assessment of preventive and therapeutic strategies for aortic injuries and diseases. A multimodal and multidisciplinary approach was adopted to characterize the transmural morphological properties of descending porcine aorta. Histology and multi-photon microscopy were used for describing the media layer micro-architecture in the circumferential-radial plane, and Fourier Transform infrared imaging spectroscopy was utilized for determining structural protein, and total protein content. The distributions of these quantified properties across the media thickness were characterized and their relationship with the mechanical properties from a previous study was determined. Our findings indicate that there is an increasing trend in the instantaneous Young׳s modulus (E), elastic lamella density (ELD), structural protein (SPR), total protein (TPR), and elastin and collagen circumferential percentage (ECP and CCP) from the inner towards the outer layers. Two regions with equal thickness (inner and outer halves) were determined with significantly different morphological and material properties. The results of this study represent a substantial step toward anatomical characterization of the aortic wall building blocks and establishment of a foundation for quantifying the role of microstructural components on the functionality of aorta.