Non-enzymatic glycation of elastin

Non-enzymatic glycation of proteins is one of the key mechanisms in the pathogenesis of diabetic complications and may be significant in the age-related changes of tissues. We investigated thein vitro glycation of human aortic -elastin, and chose and adapted methods for evaluating the degree and kinetics of glycation. -Elastin was prepared from thoracic aortas of young accident victims and glycated by incubating with different glucose concentrations (25, 50, 75 and 100 mmol/l) in 0.2 M phosphate buffer, pH 7.8 for 30 days, at 37°C. The degree of glycation was measured by three colorimetric methods,i.e. Nitroblue tetrazolium, 2-thiobarbituric acid and hydrazine; by aminophenyl-boronate affinity chromatography which determines Amadori products; and by a fluorescence method which determines advanced glycosylation end products. The highest degree of glycation was found on day 3 after the beginning of incubation. Fluorescence, as an index of advanced glycation, consistently increased from days 5 to 24. Investigation of the properties of glycated elastin may help in understanding the importance of this long-lived protein for the age-related changes in tissues and for diabetic complications.