Consequences of diabetes mellitus or liver cirrhosis on total collagen in human skin biopsies.

In this work, we studied the changes in human skin collagen occurring in diabetes mellitus and liver cirrhosis. The original methodology, based on the determination of the amino acids proline, 4-hydroxyproline, hydroxylysine, glycine and alanine, allowed us to reveal in skin a change in collagen in diabetes mellitus but none in liver cirrhosis. This biochemical evidence was correlated to the histological investigation. Moreover, diabetes mellitus did not involve any changes in hydroxylation of polypeptidic lysine. This latter observation was in accordance with the accumulation of normal collagen regarding amino acid composition only, and the results suggest a preferential accumulation of collagen type III in skin, in diabetes mellitus.