Microscopic study of aorta in relation of different age groups: an observational study

Abstract

A detailed microscopic study was carried out to see the changes in histological pattern of abdominal aorta in different age group ranging from new born to 70 years. 62 formalin-fixed specimens of either sex were studied. Thickness of tunica intima was minimal during infancy and it could not be measured, where as in the age group 60 years and above thickness of tunica intima ranged between 385 and 450 µs. While during infancy mean thickness of tunica media was 335 µs [ranged 240-385 µs]. It reaches to the maximum mean thickness of 805 in the age group 40-60 years. But in 60 years and above age group mean thickness of tunica media decreased to 660. All three layers of the arterial wall can be identified in infants. Tunica intima consists of internal elastic lamina and endothelium. Sub-endothelial layer is scarcely perceptible. Elastic fibers on tunica media are long and parallel, uniformly arranged and thicker than adult aorta. In the earlier childhood sub-endothelial connective tissue layer becomes more apparent. In adults thickness of tunica intima increases while tunica media appears thin over regional intimal hypertrophy, but in the old age diffuse intimal hypertrophy is seen. Tunica intima become half to two third of tunica media. Hyalination of collagen tissue of media occurs with loss of normal staining properties of elastic tissue. Elastic laminae become thinned and show fragmentation with occasional clumping. These changes are more prominent near inner media. Adventitia is thicker than media in infants and becomes thinner with age.