Comparison of microanatomy of ascending aorta and pulmonary trunk with age: A cross-sectional study

Abstract

Cardiovascular disease (CVD) accounts for the leading cause of mortality worldwide and it has a strong association with age. Aging brings about structural and functional changes in vessels, culminating in CVD. This study aims at determining and comparing the structural age changes in the two great vessels of heart, ascending aorta (AA) and pulmonary trunk (PT).Human ascending aorta and pulmonary trunk samples were obtained during autopsy from 55 individuals of different age group. After processing, they were stained with eosin haematoxylin and special stains to identify connective tissue fibres and smooth muscle cells. Thickness of each tunic of the vessel wall, full wall thickness, quantity of smooth muscle cells and severity of fragmentation of elastic fibres were detected.In all age groups, PT was thinner than AA. Average full wall thickness of AA was greatest in the sixth decade of life while that of PT in the fourth decade. Elastic fibres were long, straight and arranged in a lamellar pattern in tunica media of both the vessels in fetal life. They underwent fragmentation from first decade of life in PT and from third decade in AA. Grade5 fragmentation was noticed only in PT. Degeneration of smooth muscle cells occurred in both the vessels with age, but was very little in PT.Both the great vessels showed degenerative changes with advancing age, but after the first decade of life, the changes were very less in PT when compared to AA.