Development of the elastin network in the walls of resistance arteries from neonatal and adult rats

Abstract

Elastin distribution within the walls of resistance vessels is complex, with discrete fibers varying in orientation across the adventitia and media as well as the more sheet‐like structure of the internal elastic lamina (IEL). These structural patterns likely subserve specific functional properties including mechanosensing, control of forces, cellular positioning, and communication between vascular cells. To understand the impact of elastin on small artery function we initiated analyses of mRNA level expression patterns measured by qPCR, and protein distribution determined by fluorescence 3D confocal imaging. Studies were performed on 2nd order mesenteric arteries from rats aged 3, 7, 11, 14 and 19 days as well as 2 mths. Elastin mRNA peaked at day 11 before declining at later times. During the postnatal period, the elastin component of the IEL of mesenteric vessels accumulated/matured progressing from a punctate/fibrous appearance into a continuous sheet. Analysis of adventitial and medial elastin during this period showed accumulation of fibers as well as re‐organization of fiber orientation. Collectively these data show marked remodeling and development of elastin networks in the walls of small arteries as they mature. The impact of elastin remodeling on vessel function, and its relationship to concurrent changes in hemodynamics, require further study. (*Co‐first authors; NIH HL095486 to GAM)