collagen

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Related to collagen fibers: connective tissue, Elastic fibers

collagen

 [kol´ah-jen]
any of a family of extracellular, closely related proteins occurring as a major component of connective tissue, giving it strength and flexibility. Numerous types exist, each composed of tropocollagen units that share a common triple-helical shape but that vary somewhat in composition between types, with the types being localized to different tissues. adj., adj collag´enous.
collagen diseases a group of diseases having in common certain clinical and histological features that are manifestations of involvement of connective tissue, i.e., those tissues that provide the supportive framework (musculoskeletal structures) and protective covering (skin and mucous membranes and vessel linings) for the body.

The basic components of connective tissue are cells and extracellular protein fibers embedded in a matrix or ground substance of large carbohydrate molecules and carbohydrate-protein complexes called mucopolysaccharides.

For the sake of clarity and organization, collagen diseases may be divided into two major groups: (1) those that are genetically determined and are a result of structural and biochemical defects, and (2) those that are acquired and in which immunological and inflammatory reactions are taking place within the tissues. Among the first group are those diseases caused by a lack of a specific enzyme necessary for proper storage and excretion of one or more mucopolysaccharides. Also included in this group are osteogenesis imperfecta, Ehlers-Danlos syndrome, and Marfan's syndrome. These disorders are distinguished by structural defects affecting the formation of the extracellular fibers called collagen.

Acquired connective tissue diseases are believed to develop as a result of at least two causative factors: a genetic factor and an abnormal immunological response. The exact role of these factors in the development of connective tissue diseases has not been firmly established, but there is strong evidence that immunological mechanisms are involved. Examples of collagen diseases that are most probably the result of an aberration of the immunological reactions that mitigate injury and inflammation of connective tissues are systemic lupus erythematosus, scleroderma, rheumatoid arthritis, rheumatic fever, polymyositis, and dermatomyositis.

col·la·gen

(kol'lă-jen),
The major protein (comprising over half of that in mammals) of the white fibers of connective tissue, cartilage, and bone; insoluble in water but can be altered to easily digestible, soluble gelatins by boiling in water, dilute acids, or alkalis. It is high in glycyl, l-alanyl, l-prolyl, and l-4-hydroxyprolyl residues, but is low in sulfur and has no l-tryptophanyl residues. It comprises a family of genetically distinct molecules all of which have a unique triple helix configuration of three polypeptide subunits known as α-chains; at least 18 types of collagen have been identified, each with a different polypeptide chain.
See also: collagen fiber.
Synonym(s): ossein, osseine, ostein, osteine
[G. koila, glue, + -gen, producing]

collagen

(kŏl′ə-jən)
n.
1. Any of a class of extracellular proteins that are composed of three coiled polypeptide chains, form strong fibers, and are the main constituents of cartilage, bone, and other connective tissues in animals.
2. Material composed principally of collagen proteins. Collagen is converted into gelatin when boiled in water.

col′la·gen′ic (-jĕn′ĭk), col·lag′e·nous (kə-lăj′ə-nəs) adj.

collagen

A fibrous protein that provides strength and elasticity to skin, bones, cartilage and connective tissues.

col·la·gen

(kol'ă-jen)
The major protein of the white fibers of connective tissue, cartilage, and bone; insoluble in water but can be altered to easily digestible, soluble gelatins by boiling in water, dilute acids, or alkalies.
See also: collagen fiber
Synonym(s): ossein, osseine, ostein, osteine.
[G. kolla, glue, + -gen, producing]

collagen

An important protein structural element in the body. Collagen fibres are very strong and, formed into bundles which are often twisted together, make up much of the connective tissue of the body. Bones are made of collagen impregnated with inorganic calcium and phosphorus salts. Vitamin C is necessary for the cross-linking and full strength of the collagen molecule.

collagen

a fibrous protein that forms the white fibres of vertebrate CONNECTIVE TISSUE. These have a high tensile strength, e.g. tendons, but are not elastic. Collagen tissues consist of a glycoprotein matrix containing densely packed collagen fibres. The basic structural unit consists of three POLYPEPTIDE chains coiled round each other to form a triple helix, joined by hydrogen bonds. There are various different types of collagen, distinguished by the ability of the helical and non-helical regions to associate into fibrils (for example type I, II, III), to form sheets (for example type IV), or to cross-link different collagen types (for example type VI, IX). Most collagen is fibrillar. Type IV is unique to the BASAL LAMINA.

Collagen

The main supportive protein of cartilage, connective tissue, tendon, skin, and bone.

collagen 

The major protein of the white fibres of connective tissue, cartilage, tendons and bones. It is strong, fibrous, insoluble in water, rich in glycine and proline and can be hydrolysed into gelatin by boiling. In the eye it forms the primary structural component of the cornea, lens capsule, ciliary body, vitreous base and sclera. Collagen material is also used to make punctal occlusion plugs used to treat keratoconjunctivitis sicca, and dissolvable therapeutic contact lenses to deliver high-dose drugs to the cornea. Mutations in collagen genes are a common cause of connective tissue disorders. See connective tissue disorders; punctal occlusion.

col·la·gen

(kol'ă-jen)
Major protein (comprising over half of that in mammals) of white fibers of connective tissue, cartilage, and bone.
[G. koila, glue, + -gen, producing]
References in periodicals archive ?
However, there was a statistically significant difference between the Xilopercha group and the other three groups, suggesting that the experimental groups, despite an initial inflammatory response, had the ability to promote tissue regeneration because the presence of collagen fibers and procollagen was noted.
Bonar's modified score was used to assess the arrangement of collagen fibers. Analysis was done on a 0-3 scale, 0 being completely normal and 3 being maximally abnormal.
Marks, "Degenerative alterations of dermal collagen fiber bundles in photodamaged human skin and UV-irradiated hairless mouse skin: Possible effect on decreasing skin mechanical properties and appearance of wrinkles," Journal of Investigative Dermatology, vol.
The mammary lobule (white arrows), which comprises groups of acini separated by collagen fiber, is visualized distinctively via their strong TPEF signals (Figure 2(a)).
But this partially disappeared at 70[degrees]C for the 10-minute group, with collagen fiber structure completely disappearing for the 20-minute and 30-minute groups.
Morphological studies demonstrated that subendothelial layer was wide and consisted of densely packed collagen fibers and individual elastic fibers.
This will certainly improve the biocompatibility, the optical transparency, and the capacity of these materials to conjugate and interact with other biomolecules, such as corneal collagen fibers.
Prent et al., "Nonlinear optical properties of type i collagen fibers studied by polarization dependent second harmonic generation microscopy," Journal of Physical Chemistry B, vol.
Mechanical loading applied using EQUicycler aligned collagen fibers increased the thickness offibers and made cells elongate along with the collagen fibers within 3D construct.
The collagen fibers were compact with moderate porosity than the native tissue.