TGF‐βS and TGF‐β type II receptor in human epidermis: Differential expression in acute and chronic skin wounds

Abstract

Exogenously applied transforming growth factor‐beta (TGF‐β) isoforms enhance wound healing processes in animal models;¹ however, little is known about the expression of endogenous TGF‐β_s and TGF‐β receptors in intact human skin or during wound healing. The present study has revealed several unexpected findings by means of in situ hybridization and immunohistology techniques. In humans, TGF‐β₃ is constitutively expressed in the epidermis of intact skin and in that of acute and chronic wounds—a pattern of expression closely mirrored by the TGF‐β type II receptor. Although not detected in intact skin, TGF‐β mRNA expression was observed in the regenerating epidermis of acute (thermal) wounds but was not found in chronic decubital (pressure) wounds. TGF‐β₂ mRNA expression was not detected in the epidermis of any human skin or wound biopsies. From these findings we suggest that constitutive expression of TGF‐β₃ is important for maintenance of epidermal differentiation and that an induction of TGF‐β₁ expression is essential for re‐epithelialization of human skin wounds. Lack of TGF‐β₁ expression in chronic pressure wounds may be associated with their protracted healing tendencies.