Elastins

Elastins are a family of extracellular matrix proteins that provide elasticity to tissues. They are synthesized as soluble precursor molecules called tropoelastin by fibroblasts and smooth muscle cells, secreted into the extracellular space, and assembled into elastic fibers. The elastic fiber core is composed of elastin, which is cross-linked to a scaffold of microfibrils, mainly fibrillin-1 and fibrillin-2. Cross-linking, driven by lysyl oxidase, converts tropoelastin into insoluble elastin and stabilizes the network.

Elastin molecules are rich in hydrophobic amino acids and form desmosine and isodesmosine cross-links between lysine residues, giving reversible extensibility. The elastin core is surrounded by microfibrils that help organize fibers and regulate elastin deposition; collagen fibers provide tensile strength complement.

Elastin is abundant in tissues requiring stretch and recoil, such as skin, lungs, and large arteries, as well as certain ligaments. It imparts resilience and allows recoil after mechanical deformation. With aging or exposure to elastases, elastin content declines and the tissue becomes stiffer, a process accelerated by smoking and inflammatory conditions.

Genetic disorders affecting elastin include ELN gene mutations that cause autosomal dominant cutis laxa and supravalvular aortic stenosis. Williams-Beuren syndrome involves a deletion of the ELN-containing region of chromosome 7, contributing to cardiovascular anomalies. Elastin turnover continues throughout life, and elastin remodeling plays a role in tissue repair and pathology.

In research, elastin- and tropoelastin-based materials are explored for tissue engineering and regenerative medicine, aiming to mimic natural elasticity in grafts and scaffolds.