TGF-BETA-S AND TGF-BETA TYPE-II RECEPTOR IN HUMAN EPIDERMIS - DIFFERENTIAL EXPRESSION IN ACUTE AND CHRONIC SKIN WOUNDS

Exogenously applied transforming growth factor-beta (TGF-beta) isoform s enhance wound healing processes in animal models;1 however, little i s known about the expression of endogenous TGF-betas and TGF-beta rece ptors in intact human skin or during wound healing. The present study has revealed several unexpected findings by means of in situ hybridiza tion and immunohistology techniques. In humans, TGF-beta3 is constitut ively expressed in the epidermis of intact skin and in that of acute a nd chronic wounds-a pattern of expression closely mirrored by the TGF- beta type II receptor. Although not detected in intact skin, TGF-beta1 mRNA expression was observed in the regenerating epidermis of acute ( thermal) wounds but was not found in chronic decubital (pressure) woun ds. TGF-beta2 mRNA expression was not detected in the epidermis of any human skin or wound biopsies. From these findings we suggest that con stitutive expression of TGF-beta3 is important for maintenance of epid ermal differentiation and that an induction of TGF-beta1 expression is essential for re-epithelialization of human skin wounds. Lack of TGF- beta1 expression in chronic pressure wounds may be associated with the ir protracted healing tendencies.