P.20 Evolving Structure-Function Correlates during Aortic Maturation and Aging

Methods: This study, combining ex-vivo extension-inflation testing [2], multiphoton microscopy and optical histology, aimed to quantify multiple microstructural parameters of primary extracellular components – collagen, elastic lamellae – and cells – endothelial, smooth muscle and adventitia cells – of the aorta with a dynamic and multiregional 3D approach. The analysis focused on the quantification and correlation of the histo-mechanical properties of the thoracic aorta as a function of age from 21 days to 1 year after birth, that is, from the time of weaning to maturation and therefore the natural aging. The parameters quantifying the three-dimensional microstructural phenomena of deposition, remodeling and removal of aortic components under pressure and stretch conditions equivalent to those in vivo were layer thicknesses, straightening, alignment and thickness of collagen bundles, number and size of elastic lamellae, density and alignment of the different vascular cells.