Keratinocytes cultured under hyperthermal conditions secrete factor(s) which can modulate dermal fibroblast...

We have studied how keratinocytes cultured under hyperthermal conditions modulate skin fibroblast growth potential and their biosynthetic phenotypes in vitro. When keratinocytes were cultured at 30, 34, 37 or 39 degrees C, the conditioned medium of the keratinocytes cultured at 39 degrees C showed a greater inhibitory activity for fibroblast proliferation and greater synthetic activities of collagen and glycosaminoglycans than those incubated at 30, 34, or 37 degrees C. Transforming growth factor (TGF) beta 1 production in skin fibroblasts was also stimulated by the keratinocyte conditioned medium cultured at 39 degrees C. The stimulating activity of collagen and glycosaminoglycan syntheses of keratinocyte conditioned medium may be explained at least partly by enhanced TGF beta 1 production. The results indicate that keratinocytes cultured at a higher temperature (39 degrees C) may secrete factor(s) which modulate both fibroblast growth and matrix synthesis. This may provide evidence that under hyperthermal conditions epidermis can influence the functions of skin fibroblasts.