Characterization of the collagen synthesized by cultured human smooth muscle cells from fetal and adult aorta.

Smooth muscle cells were grown from explants of the tunica media of fetal and adult human aorta. Collagen was isolated after incubation with [14C]glycine and was characterized by ion-exchange chromatography. All cells investigated synthesized two types of collagen: Type I (chain composition [alpha1(I)]2alpha2) and type III (chain composition [alpha1(III)]3). The collagen made by cells from adult donors contained approximately 70% type I and 30% type III collagen. This corresponds to the collagen composition in teh original tissue. No age-relate change in the type I/type III ratio was found with cells from donors between 9 and 67 years of age. On the other hand, the type III portion of the collagen made by fetal cells was markedly less (about 15-20% of total collagen).