Topically applied growth factors change skin cytoplasmic creatine kinase activity and distribution and produce abnormal keratinocyte differentiation in murine skin

BACKGROUND/PURPOSE: The skin has a functional and active phosphocreatine (PCR)/creatine kinase (CPK) system that regenerates adenosine triphosphate energy reserves during periods of ischemia. The objective of this study was to evaluate how topically applied growth factors affect CPK activity and distribution, and what histological changes growth factors induce in murine skin. METHODS: Epidermal growth factor (EGF), transforming growth factor alpha (TGF-alpha) and suramin (growth factor inhibitor) were applied to murine skin for nine days before mice were sacrificed and CPK level and distributions were measured. RESULTS: TGF-alpha considerably increased CPK activity. Both EGF and TGF-alpha induced a CPK MM to CPK BB transition and histologically induced abnormal differentiation of keratinocytes. CONCLUSION: The skin PCR/CPK system is affected by growth factors. Furthermore, this system appears to play an important role, both in the normal physiology of skin and pathophysiological conditions such as psoriasis and carcinogenesis.