Elastin variations implicating in vascular smooth muscle cells phenotype in human tortuous arteries

The aim of the present work was to study the morphological implications bet ween the elastin and the phenotypic expression of the vascular smooth muscl e cells. For this purpose, sixty human tortuous arteries from different ter ritories have been studied. We have measured the morphometric indexes Intim al Thickening Index and Elastolyse Index and they have been quantified with computer system analysis, image-colour corresponding to the orcein and Ver hoeff reactions for detecting elastin and the alpha-actin in the smooth mus cle cells. We compared both territorial arteries from the cranial and from abdominal origin. The elastin concentration was similar in both territories , but not its morphology according to its spatial distribution. We have obs erved a relationship between the elastin structural organisation from the m edia of arteries and of the internal elastic lamina in these territories an d the variation of reactivity to the smooth muscle cr-actin as a marker of the phenotypic state. Our results confirm the hypothesis that elastin, besides intervening in the architecture of the arterial wall, is a factor implicated in the phenotypi c variability of the smooth muscle cells and in the development and evoluti on of the intimal thickenings in human atherosclerosis.