Editing Cartilage (section)

=== Disease ===
{{Main|Chondropathy}}
Several diseases can affect cartilage. [[Chondrodystrophies]] are a group of diseases, characterized by the disturbance of growth and subsequent [[ossification]] of cartilage. Some common diseases that affect the cartilage are listed below.
* [[Osteoarthritis]]: Osteoarthritis is a disease of the whole joint, however, one of the most affected tissues is the articular cartilage. The cartilage covering bones (articular cartilage—a subset of hyaline cartilage) is thinned, eventually completely wearing away, resulting in a "bone against bone" within the joint, leading to reduced motion, and pain. Osteoarthritis affects the joints exposed to high stress and is therefore considered the result of "wear and tear" rather than a true disease. It is treated by [[arthroplasty]], the replacement of the joint by a synthetic joint often made of a stainless steel alloy ([[cobalt]] chromoly) and [[ultra-high-molecular-weight polyethylene]]. [[Chondroitin sulfate]] or [[glucosamine]] sulfate supplements, have been claimed to reduce the symptoms of osteoarthritis, but there is little good evidence to support this claim.<ref>{{Cite news | url=https://www.bbc.co.uk/news/health-11330747 | work=BBC News | title=Supplements for osteoarthritis 'do not work' | date=16 September 2010}}</ref> In osteoarthritis, increased expression of inflammatory cytokines and chemokines cause aberrant changes in differentiated chondrocytes function which leads to an excess of chondrocyte catabolic activity, mediated by factors including matrix [[metalloproteinase]]s and [[aggrecanase]]s.<ref>{{Cite journal |last1=Ansari |first1=Mohammad Y. |last2=Ahmad |first2=Nashrah |last3=Haqqi |first3=Tariq M. |date=2018-09-05 |title=Butein Activates Autophagy Through AMPK/TSC2/ULK1/mTOR Pathway to Inhibit IL-6 Expression in IL-1β Stimulated Human Chondrocytes |journal=Cellular Physiology and Biochemistry |volume=49 |issue=3 |pages=932–946 |doi=10.1159/000493225 |pmid=30184535 |s2cid=52166938 |issn=1015-8987|doi-access=free }}</ref>
* Traumatic rupture or detachment: The cartilage in the knee is frequently damaged but can be partially repaired through [[knee cartilage replacement therapy]]. Often when athletes talk of damaged "cartilage" in their knee, they are referring to a damaged meniscus (a [[fibrocartilage]] structure) and not the articular cartilage.
* [[Achondroplasia]]: Reduced proliferation of chondrocytes in the epiphyseal plate of long bones during infancy and childhood, resulting in [[dwarfism]].
* [[Costochondritis]]: Inflammation of cartilage in the ribs, causing [[chest pain]].
* [[Spinal disc herniation]]: Asymmetrical compression of an [[intervertebral disc]] ruptures the sac-like disc, causing a [[hernia]]tion of its soft content. The hernia often compresses the adjacent nerves and causes back pain.
* [[Relapsing polychondritis]]: a destruction, probably [[autoimmune]], of cartilage, especially of the nose and ears, causing disfiguration. Death occurs by [[asphyxia]]tion as the larynx loses its rigidity and collapses.

[[Neoplasm|Tumors]] made up of cartilage tissue, either [[benign tumor|benign]] or [[cancer|malignant]], can occur. They usually appear in bone, rarely in pre-existing cartilage. The benign tumors are called [[chondroma]], the malignant ones [[chondrosarcoma]]. Tumors arising from other tissues may also produce a cartilage-like matrix, the best-known being [[pleomorphic adenoma]] of the [[salivary gland]]s.

The matrix of cartilage acts as a barrier, preventing the entry of [[lymphocyte]]s or diffusion of [[immunoglobulins]]. This property allows for the [[Organ transplantation|transplantation]] of cartilage from one individual to another without fear of tissue rejection.