Collagen species in human aorta: with special reference to basement membrane-associated collagens in the intima and media and their alteration with atherosclerosis.

Collagen species, especially basement membrane or short chain types, of human aorta extracted by limited and repeated pepsin digestions were investigated as to their type dependent solubility by sodium dodecyl sulfate-polyacrylamide gel electrophoresis after differential salt precipitation and cyanogen bromide cleavage. Basement membrane-associated collagens, i.e., types IV, V and VI, were more extractable in the earlier limited pepsin digests than in the later repeated ones, whereas type I collagen was continually extracted. The content of collagen type IV as well as that of type V increased with the proliferative fibrotic process in the intima including the media. Basement membrane collagen type IV showed heterogenous molecular sizes, including alpha 1(IV) and alpha 2(IV) chains. The alpha 3(V) chain of type V collagen was found in addition to the alpha 1(V) and alpha 2(V) chains. Short chain collagen type VI was detected in the intima and media at a position corresponding to 145 Kd and was reduced to fragments of around 45 Kd.