Elastic fiber

(outer lining) of the human lung Elastic fibers are found in the skin, lungs, arteries, veins, connective tissue proper, elastic cartilage, periodontal ligament, fetal tissue and other tissues which must undergo mechanical stretching. ==Histology==

Elastic fibers stain well with aldehyde fuchsin, orcein, and Weigert's elastic stain in histological 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. Alpha-1 antitrypsin deficiency is a genetic disorder where elastin is excessively degraded by elastase, a degrading protein released by neutrophils during the inflammatory response. This leads most often to emphysema and liver disease in affected individuals. Buschke–Ollendorff syndrome, Menkes disease, pseudoxanthoma elasticum, and Marfan's syndrome have been associated with defects in copper metabolism and lysyl oxidase or defects in the microfibril (defects in fibrillin, or fibullin for example). Hurler disease, a lysosomal storage disease, is associated with an altered elastic matrix. Hypertension and some congenital heart defects are associated with alterations in the great arteries, arteries, and arterioles with alterations in the elastic matrix. ==Elastosis==

Elastosis is the buildup of elastic fibers in tissues, and is a form of degenerative disease. 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. == See also ==