Electrical stimulation of transforming growth factor-beta 1 secretion by human dermal fibroblasts and the U937 human monocytic cell line

The in vitro effects on human dermal fibroblasts and the U937 human monocyt ic cell line of three phases of electrical microcurrents generated by the A CE Stimulator were investigated. The growth and viability of growing and co nfluent dermal fibroblasts were not directly influenced by the separate mic rocurrent phases. One form of microcurrent (designated phase 1) stimulated both dermal fibroblasts and U937 cells to secrete transforming growth facto r-beta1 (TGF-beta1), which is an important regulator of cell-mediated infla mmation and tissue regeneration, but none of the three phases stimulated se cretion of the pro-inflammatory cytokine interleukin-6 by U937 cells. The s timulation of TGF-beta1 secretion in these experiments was not dramatic (a median increase over control levels of 20-30%), although it could be biolog ically significant.