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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/05/11 00:09:05」(JST)

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Fibrosis is the formation of excess fibrous connective tissue in an organ or tissue in a reparative or reactive process.^[1] This can be a reactive, benign, or pathological state. In response to injury, this is called scarring, and if fibrosis arises from a single cell line, this is called a fibroma. Physiologically, fibrosis acts to deposit connective tissue, which can obliterate the architecture and function of the underlying organ or tissue. Fibrosis can be used to describe the pathological state of excess deposition of fibrous tissue, as well as the process of connective tissue deposition in healing.^[2] Defined by the pathological accumulation of extracellular matrix (ECM) proteins, fibrosis results in scarring and thickening of the affected tissue, it is in essence an exaggerated wound healing response which interferes with normal organ function.^[3]

Physiology

Fibrosis is similar to the process of scarring, in that both involve stimulated fibroblasts laying down connective tissue, including collagen and glycosaminoglycans. The process is initiated when immune cells such as macrophages release soluble factors that stimulate fibroblasts. The most well characterized pro-fibrotic mediator is TGF beta, which is released by macrophages as well as any damaged tissue between surfaces called interstitium. Other soluble mediators of fibrosis include CTGF, platelet-derived growth factor (PDGF), and Interleukin 4 (IL-4). These initiate signal transduction pathways such as the AKT/mTOR^[4] and SMAD^[5] pathways that ultimately lead to the proliferation and activation of fibroblasts, which deposit extracellular matrix into the surrounding connective tissue. This process of tissue repair is a complex one, with tight regulation of ECM synthesis and degradation ensuring maintenance of normal tissue architecture. However, the entire process, although necessary, can lead to a progressive irreversible fibrotic response if tissue injury is severe or repetitive, or if the wound healing response itself becomes deregulated.^[3]

Examples of fibrosis

Fibrosis can occur in many tissues within the body, typically as a result of inflammation or damage, and examples include:

Micrograph showing cirrhosis of the liver. The tissue in this example is stained with a trichrome stain, in which fibrosis is colored blue. The red areas are the nodular liver tissue

Lungs

Pulmonary fibrosis
- Cystic fibrosis
- Idiopathic pulmonary fibrosis (idiopathic meaning the cause is unknown)
Radiation-induced lung injury following treatment for cancer

Liver

Cirrhosis

Heart

Atrial Fibrosis
Endomyocardial fibrosis
Old myocardial infarction

Brain

glial scar

Other

Arterial stiffness
Arthrofibrosis (knee, shoulder, other joints)
Crohn's Disease (intestine)
Dupuytren's contracture (hands,fingers)
Keloid (skin)
Mediastinal fibrosis (soft tissue of the mediastinum)
Myelofibrosis (bone marrow)
Peyronie's disease (penis)
Nephrogenic systemic fibrosis (skin)
Progressive massive fibrosis (lungs); a complication of coal workers' pneumoconiosis
Retroperitoneal fibrosis (soft tissue of the retroperitoneum)
Scleroderma/systemic sclerosis (skin, lungs)
Some forms of adhesive capsulitis (shoulder)

References

^ Birbrair, Alexander; Zhang, Tan; Files, Daniel C.; Mannava, Sandeep; Smith, Thomas; Wang, Zhong-Min; Messi, Maria L.; Mintz, Akiva; Delbono, Osvaldo (2014-11-06). "Type-1 pericytes accumulate after tissue injury and produce collagen in an organ-dependent manner". Stem Cell Research & Therapy. 5 (6): 122. doi:10.1186/scrt512. ISSN 1757-6512. PMC 4445991 . PMID 25376879.
^ Glossary of dermatopathological terms. DermNet NZ
^ ^a ^b Neary; Watson & Baugh (01/10/2015). "Epigenetics and the overhealing wound: the role of DNA methylation in fibrosis". Fibrogenesis & Tissue Repair. 8 (1). doi:10.1186/s13069-015-0035-8. Retrieved 2016-04-13. Check date values in: |date= (help)
^ Mitra A, Luna JI, Marusina AI, Merleev A, Kundu-Raychaudhuri S, Fiorentino D, Raychaudhuri SP, Maverakis E (2015). "Dual mTOR Inhibition Is Required to Prevent TGF-β-Mediated Fibrosis: Implications for Scleroderma.". J Invest Dermatol. 135 (11): 2873–6. doi:10.1038/jid.2015.252. PMC 4640976 . PMID 26134944.
^ Leask A, Abraham DJ (2004). "TGF-beta signaling and the fibrotic response". FASEB Journal. 18 (7): 816–827. doi:10.1096/fj.03-1273rev. PMID 15117886.

External links

International Scar Meeting in Tokyo 2010 International Scar Meeting

UpToDate Contents

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1. 肝線維症の病因 pathogenesis of hepatic fibrosis
2. 肝線維症の非侵襲的評価に用いられる検査 tests used for the noninvasive assessment of hepatic fibrosis
3. 熱傷再建の原則：四肢および所属リンパ節領域 principles of burn reconstruction extremities and regional nodal basins
4. 骨軟化症の疫学および病因 epidemiology and etiology of osteomalacia
5. ケロイド keloids

English Journal

The role of matrix metalloproteinases in muscle and adipose tissue development and meat quality: A review.

Christensen S1, Purslow PP2.
Meat science.Meat Sci.2016 Sep;119:138-46. doi: 10.1016/j.meatsci.2016.04.025. Epub 2016 Apr 21.
Matrix metalloproteinases (MMPs) are a group of enzymes that degrade extracellular matrix components but are also important signaling molecules that regulate many biological processes including muscle, adipose and connective tissue development. Most recently it has been discovered that MMPs act as i
PMID 27180222

Influence of cytokine and cytokine receptor gene polymorphisms on the degree of liver damage in patients with chronic hepatitis C.

Moreira ST1, Silva GF2, de Moraes CF3, Grotto RM3, de Moura Campos Pardini MI3, Bicalho Mda G4, Moliterno RA5.
Meta gene.Meta Gene.2016 Apr 21;9:90-6. doi: 10.1016/j.mgene.2016.04.003. eCollection 2016.
Hepatic fibrosis may be the result of repetitive injury to hepatocytes caused by HCV infection and the immune response to it. Cytokines regulate the inflammatory response to injury and modulate hepatic fibrogenesis. Single nucleotide polymorphisms (SNPs) located in cytokine genes may influence the c
PMID 27200267

Human precision-cut liver slices as a model to test antifibrotic drugs in the early onset of liver fibrosis.

Westra IM1, Mutsaers HA2, Luangmonkong T2, Hadi M3, Oosterhuis D2, de Jong KP4, Groothuis GM3, Olinga P5.
Toxicology in vitro : an international journal published in association with BIBRA.Toxicol In Vitro.2016 Sep;35:77-85. doi: 10.1016/j.tiv.2016.05.012. Epub 2016 May 26.
Liver fibrosis is the progressive accumulation of connective tissue ultimately resulting in loss of organ function. Currently, no effective antifibrotics are available due to a lack of reliable human models. Here we investigated the fibrotic process in human precision-cut liver slices (PCLS) and stu
PMID 27235791

Japanese Journal

哺乳類第4番目のグロビン,サイトグロビンの発見 (特集第4のグロビン : サイトグロビンの機能)

吉里勝利,河田則文
細胞 45(13), 601-604, 2013-12
NAID 40019987660

CCL2/CCR2 augments the production of transforming growth factor-beta1, type 1 collagen and CCL2 by human CD45-/collagen 1-positive cells under high glucose concentrations

Hara Akinori,Sakai Norihiko,Furuichi Kengo,Sakai Yoshio,Takeya Motohiro,Bucala Richard,Mukaida Naofumi,Takuwa Yoh,Matsushima Kouji,Kaneko Shuichi,Wada Takashi
Clinical and Experimental Nephrology 17(6), 793-804, 2013-12
… Background: The migration and activation of circulating profibrotic cells including fibrocytes by the action of the chemokine/chemokine receptor system has been implicated in pathological fibrogenesis. …
NAID 120005368211

非環式レチノイドは血小板由来増殖因子(PDGF)-C 過剰発現肝発癌モデルマウスの肝線維化・肝発癌を抑制する

岡田光
金沢大学十全医学会雑誌 122(2), 35-36, 2013-06
… Peretinoin inhibited the signaling pathways of fibrogenesis, angiogenesis, and Wnt/β-catenin in Pdgfc transgenic mice. …
NAID 120005324082

Related Pictures

★リンクテーブル★

リンク元	「fibrillization」「fibril formation」「線維形成」「fibrogenic」「fiber formation」

「fibrillization」

Fibrosis
	Micrograph of a heart showing fibrosis (yellow - left of image) and amyloid deposition (brown - right of image). Movat's stain.
Classification and external resources
Specialty	Pathology
MeSH	D005355
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