Elastin, an important structural protein of extracellular matrix (ECM), is the main component of elastic fiber, which provides resilience and elasticity to many tissues, such as the skin, lungs, ligaments and arterial walls.Human neutrophil elastase (HNE), a serine protease primarily located in the azurophil granules of polymorphonuclear leukocytes, is the only enzyme capable of degrading ECM proteins, such as elastin, collagen, fibronectin, laminin and proteoglycan.Biologically, elastase activity significantly increases with age and results in a reduced skin elastic property.