Repair growth factors and the importance of the liver framework
THE CONTEXT
Growth factors support repair through effects on fibroblasts, keratinocytes, blood vessels, and extracellular matrix. Liver regeneration also depends on preservation of tissue structure.
Fibroblast growth factors
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Fibroblast growth factors include acidic FGF-1 and basic FGF-2. Their sources include macrophages, mast cells, endothelial cells, and many other cell types.
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These factors are chemotactic and mitogenic for fibroblasts and stimulate angiogenesis and extracellular matrix (ECM) protein synthesis.
Transforming growth factor beta
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Transforming growth factor beta is produced by platelets, T lymphocytes, macrophages, endothelial cells, keratinocytes, smooth muscle cells, and fibroblasts.
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It is chemotactic for leukocytes and fibroblasts, stimulates ECM protein synthesis, and suppresses acute inflammation.
Keratinocyte growth factor
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Keratinocyte growth factor, also called FGF-7, is produced by fibroblasts.
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It stimulates keratinocyte migration, proliferation, and differentiation.
Liver regeneration and scarring
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Extensive liver destruction with collapse of the reticulin framework, as in a liver abscess, leads to scarring even when the remaining liver cells retain the capacity to regenerate.
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The liver's marked regenerative capacity is demonstrated by growth after partial hepatectomy, which may be performed for tumor resection or living-donor hepatic transplantation.