High-performance liquid chromatographic determination of desmosine and isodesmosine in tissues and its application to studies of alteration of elastin induced by atherosclerosis.

A rapid, sensitive high-performance liquid chromatographic method has been developed for the determination of desmosine (DES) and isodesmosine (IDE), the specific cross-linking amino acids of elastin, in the tissue hydrolysates of rats. DES and IDE in the hydrolysate samples were separated on a C18 column using 0.1 M phosphate buffer-acetonitrile (2.8:1) containing 20 mM sodium dodecyl sulphate (final pH 4.5) followed by detection at 270 nm. The recoveries of the added standards of DES and IDE from the aorta hydrolysate samples were 99.6 +/- 2.7% and 98.4 +/- 1.8%, respectively (n = 10). At DES and IDE concentrations of 2 micrograms/ml, within- and between-run precisions were 1.11-1.85% and 0.55-1.24%, respectively. The detection limits of DES and IDE were 0.1 microgram/ml with a 50-microliter injection at a signal-to-noise ratio of 3. The method was successfully applied to a study of the alteration of DES and IDE contents (i.e. elstin contents) in the tissues of rats treated with beta-aminopropionitrile and an atherogenic diet. A negative correlation between the contents of these amino acids and of cholesterol was noted in the atherosclerotic aorta.