Growth factors in the anterior segment: role in tissue maintenance, wound healing and ocular pathology

Wound healing following refractive surgery in hens

“…Both processes are regulated by several cytokines synthesized and released by the epithelium, i.e., transforming growth factor (TGF)-b and interleukin 1 and 6 (Girard et al, 1991;Malecaze et al, 1997). The synthesis of new tissue requires proliferation, migration, and differentiation of epithelial cells, which are stimulated by growth factors secreted by keratocytes, epithelial growth factor (EGF), keratinocyte growth factor, and hepatocyte growth factor (Klenkler and Sheardown, 2004;Wilson et al, 1994). The synthesis of new tissue also requires proliferation of the remaining keratocytes (Zieske, 2000) that are regulated by EGF, TGF-b, platelet-derived growth factor, and fibroblast growth factor, secreted by epithelial and inflammatory cells (Baldwin and Marshall, 2002) and the synthesis of a new extracellular matrix secreted by fibroblasts.…”

TGFβ pathobiology in the eye

“…This includes modulation of cell migration and proliferation, cell death, and protein synthesis during development, tissue repair, and other physiological or pathological processes. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] In most cases, TGFb enhances extracellular matrix production and suppresses cell proliferation. Moreover, TGFb is capable of inducing a number of growth factors, that is, connective tissue growth factor (CTGF), platelet-derived growth factor (PDGF), fibroblast growth factors (FGFs), and vascular endothelial growth factor (VEGF), as well as TGFb1 itself.…”

Activation of the epidermal growth factor receptor by hydrogels in artificial tears

“…A very large number of studies have indicated that EGF accelerates healing of wounds in the cornea in a variety of different animal models and in humans (for reviews see Baldwin and Marshall, 2002;Imanishi et al, 2000;Klenkler and Sheardown, 2004;Lu et al, 2001; for reviews see Schultz et al, 1994). A key to success is to apply constant stimulation either by frequent applications or using some continuous release device (Brown et al, 1988;Hori et al, 2007;Sheardown et al, 1993) Soluble hydrogels may reside on the cell surface for hours (Garrett et al, 2007;Lee et al, 2000;Peppas and Sahlin, 1996;Salamat-Miller et al, 2005;Sudhakar et al, 2006), and even more prolonged contact may be achieved when applied with continuous release devices.…”

“…Therefore it is likely that the hydrogels have effects in addition to stimulating the EGF receptor. The corneal epithelium contains numerous growth factor signaling systems that impact on cell motility (Klenkler and Sheardown, 2004;Wilson et al, 2003), so it is possible that the hydrogels have effects on other receptors. In addition, carboxymethyl cellulose binds to the extracellular matrix and enhances adhesion of corneal epithelial cells, so an effect on the matrix could also contribute to increased cell motility and wound healing (Garrett et al, 2007).…”