Transforming growth factor (TGF)-beta(1), -beta(2), -beta(3), basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) expression in keratinocytes of burn scars

Keratinocytes are increasingly recognized as key regulators of skin inflamm ation and remodeling, as they are capable of producing growth factors and c ytokines that are important mediators in the wound healing process. We inve stigated the expression and distribution of TGF-beta 1 mRNA by mRNA in situ hybridization and of TGF-beta 1, TGF-beta 2, TGF-beta 3, bFGF and VEGF pro tein expression using immunohistochemistry in spontaneously healed, partial -thickness burns and compared this with the expression of these markers in matched unburned skin, This was done to assess their role in the remodeling phase of burn wound healing. Punch biopsies were taken from both partial-t hickness burns after re-epithelialization and from matched, unburned skin. At 4 and 7 months post-burn, biopsies were taken of normotrophic and hypert rophic scars that had developed in these wounds. We observed a higher expre ssion of all mentioned growth factors in keratinocytes in scars at 1 month post-burn compared with matched unburned skin, At 4 months, keratinocytes s till displayed a higher expression of TGF-beta 3 acid bFGF, but the express ion of TGF-beta 1, TGF-beta 2 and VEGF was normalized. The expression of TG F-beta 3 in the epidermis of hypertrophic scars was slightly higher than in normotrophic scars. At 7 months post-burn, all growth factors studied show ed a normal expression on keratinocytes, Our results suggest that keratinocytes are not only involved in re-epitheli alization, but also in the scar maturation, The data support the idea that keratinocytes not only respond to cytokines and growth factors in an autocr ine fashion, but also exert regulatory paracrine effects on contiguous cell s.