desmosine and Aortic-Valve-Insufficiency

The activity of lysyl oxidase, the cross-linking enzyme of elastin and collagen, was measured in culture media of human skin fibroblasts, human aortic medial smooth muscle cells (SMCs) and adventitial fibroblasts using [3H]lysine-labelled elastin substrate. In addition, biosynthesis of isodesmosine and desmosine, the cross-linking amino acids of elastin, was studied by metabolic labelling with [14C]lysine and subsequent amino acid chromatography of protein hydrolysates. Lysyl oxidase activity in culture media of skin fibroblasts and aortic smooth muscle cells increased with the growth of the cell population and was at the highest level in cultures of high cell density. Lysyl oxidase activity in the aortic cell cultures was about three times that of skin fibroblasts. Aortic smooth muscle cells synthesized at least 100 times more desmosines than skin or adventitial fibroblasts. No differences were observed in lysyl oxidase activity and synthesis of desmosines between aortic smooth muscle cells or skin fibroblasts from patients with the Marfan syndrome or other annulo-aortic ectasia (dilatation of the ascending aorta) and the corresponding controls.

Topics: Adolescent; Adult; Amino Acid Oxidoreductases; Amino Acids; Aorta; Aortic Diseases; Aortic Valve Insufficiency; Cell Line; Cells, Cultured; Child; Desmosine; Dilatation, Pathologic; Female; Fibroblasts; Humans; Male; Marfan Syndrome; Middle Aged; Protein-Lysine 6-Oxidase; Skin