Elastic fiber
Elastic fiber | |
---|---|
Identifiers | |
FMA | 63868 |
Anatomical terminology |
Elastic fibers (or yellow fibers) are an essential component of the extracellular matrix composed of bundles of proteins (elastin) which are produced by a number of different cell types including fibroblasts, endothelial, smooth muscle, and airway epithelial cells.[1] These fibers are able to stretch many times their length, and snap back to their original length when relaxed without loss of energy. Elastic fibers include elastin, elaunin and oxytalan.
Elastic fibers are formed via elastogenesis,
Following deposition onto microfibrils tropoelastin is insolubilized via extensive crosslinking by members of the lysyl oxidase and lysyl oxidase like family of copper-dependent amine oxidases into amorphous elastin, a highly resilient, insoluble polymer that is metabolically stable over a human lifespan.[1] These two families of enzymes react with the many lysine residues present in tropoelastin to form reactive aldehydes and allysine via oxidative deamination.[11]
These reactive aldehydes and allysines can react with other lysine and allysine residues to form desmosine, isodesmosine, and a number of other polyfunctional crosslinks that join surrounding molecules of tropoelastin into an extensively crosslinked elastin matrix. This process creates a diverse array of intramolecular and intermolecular crosslinks[12] These unique crosslinks are responsible for elastin's durability and persistence. Maintenance of crosslinked elastin is carried out by a number of proteins including lysyl oxidase-like 1 protein.[13]
Mature elastic fibers consist of an amorphous
Distribution
Elastic fibers are found in the
Elastic fibers are absent from
Histology
Elastic fibers stain well with
sections.The permanganate-bisulfite-toluidine blue reaction is a highly selective and sensitive method for demonstrating elastic fibers under polarizing optics. The induced birefringence demonstrates the highly ordered molecular structure of the elastin molecules in the elastic fiber. This is not readily apparent under normal optics.
Defects and disease
There is evidence to believe that certain defects of any components of the elastic matrix may impair and alter the structural appearance of elastic and collagen fibers.
Cutis laxa and Williams syndrome have elastic matrix defects that have been directly associated with alterations in the elastin gene.
Elastosis
Elastosis is the buildup of elastic fibers in tissues, and is a form of degenerative disease.[17] There are a multitude of causes, but the most commons cause is actinic elastosis of the skin, also known as solar elastosis, which is caused by prolonged and excessive sun exposure, a process known as photoaging. Uncommon causes of skin elastosis include elastosis perforans serpiginosa, perforating calcific elastosis and linear focal elastosis.[17]
Condition | Distinctive features | Histopathology |
---|---|---|
Actinic elastosis (most common, also called solar elastosis) |
Elastin replacing collagen fibers of the reticular dermis
|
|
Elastosis perforans serpiginosa | Degenerated elastic fibers and transepidermal perforating canals (arrow in image points at one of them)[18] | |
Perforating calcific elastosis | Clumping of short elastic fibers in the dermis.[18] | |
Linear focal elastosis | Accumulation of fragmented elastotic material within the papillary dermis and transcutaneous elimination of elastotic fibers.[18] |
See also
References
- ^ S2CID 196458819.
- PMID 15837523.
- ^ PMID 34355407.
- PMID 25960419.
- PMID 26601954.
- PMID 19016471.
- S2CID 4343659.
- PMID 21081222.
- PMID 10419484.
- PMID 18547105.
- S2CID 31863161.
- PMID 30108173.
- PMID 14745449.
- PMID 15748998.
- ISBN 9781893357259. Archived from the originalon June 20, 2018. Retrieved December 28, 2016.
Elastic fibers are absent from scarring processes such as scars, keloids, and dermatofibromas
- ^ "Connective Tissue". Archived from the original on November 7, 2008.
- ^ a b Wright B. "Elastosis". DermNet NZ.
- ^ license
External links
- Histology image: 00801ooa – Histology Learning System at Boston University - "Connective Tissue elastic fibers "
- UIUC Histology Subject 328
- Anatomy photo: TermsCells&Tissues/connective/elastic/elastic2 - Comparative Organology at University of California, Davis - "Connective tissue, elastic (LM, High)"