élasztin

Elastin, sometimes spelled elasztin in non-English texts (also written as élasztin in some languages), is an extracellular matrix protein that provides elasticity to tissues. It is produced by fibroblasts and smooth muscle cells and is a major component of connective tissues such as the dermis of the skin, lung parenchyma, arterial walls, ligaments, and certain tendons. Elastin allows tissues to resume shape after stretching or deformation.

Elastin fibers are formed from tropoelastin monomers that are secreted into the extracellular space and assembled with microfibrils, notably those containing fibrillin. Tropoelastin monomers align in amorphous networks and are cross-linked by lysyl oxidase, generating desmosine- and isodesmosine-containing cross-links that give elastic resilience. The resulting elastic fibers are insoluble and highly resilient, with a long tissue half-life.

Genetics and regulation: The elastin gene (ELN) encodes tropoelastin. Mutations or haploinsufficiency can cause connective tissue disorders such as cutis laxa and supravalvular aortic stenosis. Elastin expression is regulated by mechanical cues and signaling pathways, including transforming growth factor-β, and decreases with aging.

Function and aging: Elastin provides passive recoil and maintains tissue integrity under cyclic stretch. Its long-lived nature means damage accumulates slowly; however, proteolytic enzymes such as matrix metalloproteinases can fragment elastin, contributing to skin wrinkles, arterial stiffness, and other age-related changes. Loss of elastin or defective fibers can lead to reduced elasticity and altered tissue mechanics.