Growth Factors in Photodamaged Skin: Clinical Pearls

Zoe Diana Draelos, MD

Dr Draelos provides us with her clinical pearls on growth factors (GF):

• GF are multifunctional peptides active in the picogram range
• GF act as signaling molecules between cells by binding to cell surface receptors
• GF modes of targeting:
  • GF release into the blood stream to reach distant targets (endocrine mode)
  • GF diffuse over short distances to affect other cells (juxtacrine mode)
  • GF influence neighboring cells (paracrine)
  • GF act on the cells in which they are produced (autocrine mode)
• GF relevant to cosmeceuticals are epidermal growth factor, keratinocyte growth factor, fibroblast growth factor, platelet-derived growth factor
• Epidermal growth factor is produced from macrophages and monocytes, it affects epithelium and endothelial cells stimulating the proliferation of keratinocytes, fibroblasts, and endothelial cells
• Keratinocyte growth factor is a small signaling molecule that binds to fibroblast growth factor receptor 2b found in the epithelialization-phase of wound healing
• Fibroblast growth factor is a very potent angiogenic factor derived from monocytes, macrophages, and endothelial cells (22 human FGFs identified) that induces proliferation of endothelial cells, keratinocytes, and fibroblasts
• Platelet derived growth factor is produced by platelets, macrophages, neutrophils, smooth muscle cells and induces proliferation of smooth muscle cells and fibroblasts
• Current controversy exists as to whether growth factors are drugs or cosmetics