Elastin is a highly elastic protein found in connective tissues that allows tissues in the body to stretch and return to their original shape. It works alongside collagen, but whereas collagen provides strength, elastin provides flexibility and resilience.
Definition:
Elastin is a structural protein that forms elastic fibers in the extracellular matrix of connective tissue. It enables tissues to recoil after stretching or contracting.
Key Characteristics:
- Highly stretchable: Can stretch up to 1.5 times its length and return to normal.
- Durable: Extremely stable and long-lasting—once produced in early life, elastin has a very slow turnover.
- Hydrophobic: Resists water, contributing to its spring-like properties.
- Made of tropoelastin: The soluble precursor that is cross-linked outside the cell to form mature elastin fibers.
Functions of Elastin:
- Gives skin its ability to stretch and bounce back.
- Helps lungs expand and contract during breathing.
- Allows arteries to stretch and recoil with blood flow.
- Supports the function of bladder, ligaments, and elastic cartilage (e.g., in the ear).
Where Elastin Is Found:
- Skin
- Lungs
- Arteries
- Elastic ligaments
- Bladder
- Certain cartilage (like the ear and epiglottis)
How It Works:
- Elastin molecules are secreted by cells like fibroblasts and smooth muscle cells as tropoelastin.
- Tropoelastin is then cross-linked by the enzyme lysyl oxidase to form an elastic network.
- These fibers can stretch under force and return to their original shape when the force is removed—similar to a rubber band.
Elastin vs. Collagen:
| Feature | Elastin | Collagen |
|---|---|---|
| Function | Flexibility and recoil | Strength and structure |
| Texture | Stretchy and flexible | Tough and rigid |
| Abundance | Less abundant than collagen | Most abundant protein in the body |
| Turnover rate | Very slow (almost none in adults) | Moderate |
Aging and Elastin:
- Elastin production peaks early in life, especially in fetal and early childhood stages.
- With age, elastin degrades and is not effectively replaced, leading to wrinkles, sagging skin, and stiffer arteries.
Clinical and Cosmetic Relevance:
- Elastin damage is common with sun exposure, smoking, and pollution.
- Skincare products may claim to support elastin, but the body doesn’t easily rebuild it once lost.
- Research is ongoing in bioengineered elastin for tissue repair and vascular grafts.