What is the pathogenesis of keloids?

Updated: Jan 30, 2020
  • Author: Ginard I Henry, MD; Chief Editor: Gregory Gary Caputy, MD, PhD, FICS  more...
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Answer

Answer

Overexuberant proliferation activity of the fibroblast occurs in the keloid scar. Fibroblast generates an excessive amount of extracellular matrix (ECM) proteins, such as collagen and fibronectin. Transforming growth factor beta (TGF-β) plays an important role in regulating fibroblast proliferative function, as well as up-regulating important metalloproteinases that contribute to keloid formation. Collagen type III production is 3 times normal in keloids, and all collagen production is associated with less crosslinking, smaller interfibrillar distance, and a more disorganized fibrillar pattern. Total collagen synthesis is 20 times normal, and the collagen-to-fibroblast ratio is also significantly altered.

A study by Touchi et al indicated that the central portion of keloids is severely ischemic. The investigators found greater expression of hypoxia-induced factor-1α, as well as less vascular density, in the center than on the periphery of these lesions. [7]


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