Transforming growth factors (TGF-α and TGF-β1) in the determination of vitality and wound age: immunohistochemical study on human skin wounds

In continuation of former investigations on proinflammatory cytokines, in the present study the relevance of the transforming growth factors TGF-α and TGF-β1 was evaluated for the diagnosis of vitality and wound age. Paraffin sections from human skin wounds due to sharp force influence, which had been collected in operations and autopsies, were investigated using immunohistochemistry. The wound age varied from a few minutes to a maximum of 6 weeks with focus on the early post-traumatic interval up to 5 h. Samples from uninjured skin were available as controls. TGF-α (n = 74) was weakly expressed in normal skin and showed a marked increase in epidermal reactivity after a wound age of approximately 10 min. The maximum was between 30 and 60 min. TGF-β1 (n = 51) revealed constitutional expression only in connective tissue. An increase of immunohistochemical reaction was partially detected even in classical stab wounds (wound age of several minutes). The immunohistochemically detectable signal concerned - presumably due to an infiltration with TGF-β-rich thrombocytes - large parts of the traumatized skin and also the epidermal layers (cellular and interstitial marking). TGF-β1 peaked after a post-traumatic interval of 30-60 min. Both factors, especially TGF-β1, remained detectable in elevated levels also in older wounds with an age of days to weeks (network in granulation tissue). TGF-α and TGF-β1 can efficiently contribute to the estimation of vitality and wound age based on the evaluation of cytokine patterns. In particular, this applies to TGF-β1 because of its easier evaluation and rapid up-regulation. Similar to other cytokines, the parallel investigation of control skin from the same individual must be recommended to eliminate variation in the basal expression.