A growth factor is a naturally occurring substance capable of stimulating cell proliferation, wound healing, and occasionally cellular differentiation.[1] Usually it is a secreted protein or a steroid hormone. Growth factors are important for regulating a variety of cellular processes.

Growth factors typically act as signaling molecules between cells. Examples are cytokines and hormones that bind to specific receptors on the surface of their target cells.

They often promote cell differentiation and maturation, which varies between growth factors. For example, epidermal growth factor (EGF) enhances osteogenic differentiation (osteogenesis or bone formation),[2] while fibroblast growth factors and vascular endothelial growth factors stimulate blood vessel differentiation (angiogenesis).

Comparison to cytokines

Growth factor is sometimes used interchangeably among scientists with the term cytokine.[3] Historically, cytokines were associated with hematopoietic (blood and lymph forming) cells and immune system cells (e.g., lymphocytes and tissue cells from spleen, thymus, and lymph nodes). For the circulatory system and bone marrow in which cells can occur in a liquid suspension and not bound up in solid tissue, it makes sense for them to communicate by soluble, circulating protein molecules. However, as different lines of research converged, it became clear that some of the same signaling proteins which the hematopoietic and immune systems use were also being used by all sorts of other cells and tissues, during development and in the mature organism.

While growth factor implies a positive effect on cell proliferation, cytokine is a neutral term with respect to whether a molecule affects proliferation. While some cytokines can be growth factors, such as G-CSF and GM-CSF, others have an inhibitory effect on cell growth or cell proliferation. Some cytokines, such as Fas ligand, are used as "death" signals; they cause target cells to undergo programmed cell death or apoptosis.

The nerve growth factor (NGF) was first discovered by Rita Levi-Montalcini, which won her a Nobel Prize in Physiology or Medicine.

List of classes

Individual growth factor proteins tend to occur as members of larger families of structurally and evolutionarily related proteins. There are many families, some of which are listed below:

In platelets

The alpha granules in blood platelets contain growth factors PDGF, IGF-1, EGF, and TGF-β which begin healing of wounds by attracting and activating macrophages, fibroblasts, and endothelial cells.

Uses in medicine

For the last two decades, growth factors have been increasingly used in the treatment of hematologic and oncologic diseases[4][5] and cardiovascular diseases[6][7] such as:

See also

References

  1. ↑ "growth factor""at Dorland's Medical Dictionary
  2. ↑ Del Angel-Mosqueda C, Gutiérrez-Puente Y, López-Lozano AP, Romero-Zavaleta RE, Mendiola-Jiménez A, Medina-De la Garza CE, Márquez-M M, De la Garza-Ramos MA (September 2015). "Epidermal growth factor enhances osteogenic differentiation of dental pulp stem cells in vitro". Head & Face Medicine. 11: 29. doi:10.1186/s13005-015-0086-5. PMC 4558932. PMID 26334535.
  3. ↑ Yorio T, Clark AF, Wax MB (2007). Ocular Therapeutics: Eye on New Discoveries. Academic Press. p. 88. ISBN 978-0-12-370585-3.
  4. ↑ Cottler-Fox M, Klein HG (April 1994). "Transfusion support of hematology and oncology patients. The role of recombinant hematopoietic growth factors". Archives of Pathology & Laboratory Medicine. 118 (4): 417–20. PMID 7909429.
  5. ↑ Aaronson SA (November 1991). "Growth factors and cancer". Science. 254 (5035): 1146–53. Bibcode:1991Sci...254.1146A. doi:10.1126/science.1659742. PMID 1659742.
  6. ↑ Domouzoglou EM, Naka KK, Vlahos AP, Papafaklis MI, Michalis LK, Tsatsoulis A, Maratos-Flier E (September 2015). "Fibroblast growth factors in cardiovascular disease: The emerging role of FGF21". American Journal of Physiology. Heart and Circulatory Physiology. 309 (6): H1029-38. doi:10.1152/ajpheart.00527.2015. PMC 4747916. PMID 26232236.
  7. ↑ Gorenoi, Vitali; Brehm, Michael U.; Koch, Armin; Hagen, Anja (2017). "Growth factors for angiogenesis in peripheral arterial disease". The Cochrane Database of Systematic Reviews. 2017 (6): CD011741. doi:10.1002/14651858.CD011741.pub2. ISSN 1469-493X. PMC 6481523. PMID 28594443.
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