Liberation of desmosine and isodesmosine as amino acids from insoluble elastin by elastolytic proteases

► The development of atherosclerosis and abdominal aortic aneurysms involves the degradation of extracellular matrix components, such as collagen and elastin. ► Releases of the elastin cross-links desmosine (DES) and isodesmosine (IDE) may reflect elastin degradation in cardiovascular diseases. ► Exposure of insoluble elastin to monocyte/macrophage-conditioned media or recombinant MMP-12 and neutrophil elastase liberated DES and IDE as amino acids. ► Elastin oxidized by reactive oxygen species (ROS) liberated more DES and IDE than did non-oxidized elastin. ► The results of this study support the exploration of free DES and IDE as biomarkers of elastin degradation.