Regional Biomechanical and Microstructural Alterations of the Ovine Main Pulmonary Artery During Postnatal Growth

Abstract

It has been estimated that worldwide 600,000 babies are born annually with significant congenital heart disease (1). Congenital heart and related vascular defects cause increased flow and pulmonary pressure leading to unfavorable vascular remodeling that results in pulmonary arterial hypertension (1). Developing tissue engineered replacements that mimic the growth and remodeling behavior of native tissue is the optimal approach in treatment of congenital arterial anomalies. The understanding of the underlying mechanisms leading to pulmonary arterial hypertension as well as replicating native pulmonary artery functionality in engineered replacements requires knowledge of native tissue mechanics and growth behavior. In the present study, we report novel information on the changes in the structure-mechanics behavior of the growing pulmonary artery.

Insights Into Regional Adaptations in the Growing Pulmonary Artery Using a Meso-Scale Structural Model: Effects of Ascending Aorta Impingement

“…As observed in our geometric studies [18,19], the focal changes in the medial region aie likely due to the impingement of relatively stiff ascending aorta on the growing PA. As observed in our geometric studies [18,19], the focal changes in the medial region aie likely due to the impingement of relatively stiff ascending aorta on the growing PA.…”

“…As observed in our geometric studies [18,19], the focal changes observed in the medial region are likely due to the impingement of relatively stiff ascending aorta on the growing PA. This effect is likely more pronounced since these two great vessels are held together within a connective tissue sheath (J. E. Mayer, Jr., private communication).…”

“…We have recently demonstrated complex patterns of spatial growth in the growing ovine PA [18,19]. Our results indicated that the spatial and temporal surface growth deformation pattems of both arteries were heterogeneous, including an increase in taper in both arteries and increase in cross-sectional ellipticity of the PA. Interestingly, contact between the PA and AA resulted in increasing spatial heterogeneity in postnatal growth, with the PA demonstrating the greatest changes.…”

From Uniaxial Testing of Isolated Layers to a Tri-Layered Arterial Wall: A Novel Constitutive Modelling Framework

“…In their work, collagen fibre orientation was inferred from histological images, and probability functions describing collagen recruitment were postulated from the literature and from a qualitative observation of collagen waviness across the wall thickness. Fata et al 11,12 chose anisotropic SEFs for modelling both collagen and elastin and used multi-photon fluorescence of the ovine pulmonary artery wall tissue subjected to biaxial testing to determine collagen and elastin orientation distributions. Moreover, the waviness of the adventitial collagen was used to define a probabilistic recruitment function describing its delayed response.…”