Degenerative changes in endothelial and smooth muscle cells from aging swine ductus arteriosus and venosus.

Degenerative changes in endothelial and smooth muscle cells from fetal, 2-month-, and 6-month-old swine ductus vasculature were observed. In fetal ductus, a discontinuous internal elastic lamina and increased extracellular mucopolysaccharide deposition were initially noted. At 2 months of age, there was widespread fibromuscular intimal thickening, the appearance of modified smooth muscle cells, increased medial fibrosis, and the occurrence of cell debris and nuclear pyknosis. Early modification of smooth muscle cells was marked by increased occurrence of lysosomes, widely dilated rough endoplasmic reticulum, and Golgi bodies. Abundant aggregates of Weibel-Palade bodies occurred in early endothelial cell degeneration. At 6 months of age, after complete anatomical closure, there was abundant lipid vacuole production by degenerated medial smooth muscle cells. This study demonstrates that at various stages of occlusion, endothelial and smooth muscle cells from ductus vasculature exhibit morphological changes which are qualitatively similar to atherosclerosis.