Studies of transforming growth factors beta 1-3 and their receptors I and II in fibroblast of keloids and hypertrophic scars

Keloids are benign skin tumours occurring during wound healing in genetically predisposed patients. They are characterized by an abnormal deposition of extracellular matrix components, particularly collagen. There is uncertain evidence that transforming growth factor-beta (TGFβ) is involved in keloid formation. Therefore we investigated the expression of TGFβ1, 2 and 3 and their receptors in keloids, hypertrophic scars and normal skin. Dermal fibroblasts were obtained from punch biopsies of patients with keloids and hypertrophic scars and from normal skin of healthy individuals. Total RNA was isolated and the expression of TGFβR1, 2 and 3 and of TGFβ receptors I and II (TGFβRI and II) was analysed by real-time PCR using the Lightcycler technique. Our data demonstrate significantly lower TGFβ2 mRNA expression in hypertrophic scar fibroblasts as compared with fibroblasts derived from keloids and normal skin (p <0.05). In contrast, TGFβ3 mRNA expression was significantly lower in keloid fibroblasts in comparison with fibroblasts derived from hypertrophic scar and normal skin (p <0.01). TGFβRI mRNA expression was significantly decreased in hypertrophic scar fibroblasts (p <0.01) and TGFβRII mRNA expression was decreased in keloids compared with hypertrophic scar fibroblasts (p <0.001). The ratio of TGFβRI/TGF/ βRII expression was increased in keloids compared with hypertrophic scar and normal skin fibroblasts. As recently supposed, an increased TGFβRI/TGFβRII ratio could promote fibrosis. Therefore our data support a possible role of TGFβRI and TGFβRII in combination with a certain TGFβ expression pattern as fibrosis-inducing factors in keloids. © 2005 Taylor & Francis.