Contributions to the study of the foetal development of physiological intimal thickening in the human uterine artery.

The morphological study of the development of "intimal thickenings" of the human uterine artery in physiological condition was performed on 72 uterine arteries obtained from foetuses from the 12th week of gestation up to birth. Our results indicate that intimal thickening is formed by the migration and displacement of mesenchymal cells around the site of origin of collateral vessel from uterine mesothelium. These cells firstly differentiate into the myoblasts and then into the myocites. During the development the internal limitans membrane separates the intimal thickening from the tunica media and the elastic fibres appearing inside possessing a muscle-elastic nature. The function of intimal thickenings is the regulation of local blood flow by means of the control of myocitic contractile capacity; these cells play a fundamental role in endothelium-intimal smooth muscle cell contact.