Human health consequences of environmentally-modulated gene expression: Potential roles of ELF-EMF induced epigenetic versus mutagenic mechanisms of disease

In order to determine if there might be biological and health consequences after exposures to extremely-low frequency electromagnetic fields (ELF-EMF) either experimentally or epidemiologically, mechanistic understanding of t he potential means by which any environmental agent can affect cells in a m ulticellular organism has to be reviewed. The goal of this limited review i s to demonstrate that, while the prevailing paradigm of the environmentally -induced acute and chronic diseases involves either cell killing (cytotoxic ity) or gene/chromosome mutations (genotoxicity), alteration of the express ion of genetic information at the transcriptional (turning genes "on" or "o ff"), translational (stabilizing or de-stabilizing the genetic message), or posttranslational (altering the gene product or protein) levels has the po tential to contribute to various diseases. This latter mechanism, "epigenet ic" toxicity, unlike the former two which are irreversible, is characterize d by threshold-like action, multiple biochemical pathways and chronic, regu lar exposures to be effective. Ultimately, epigenetic toxicants affect one of four potential cell states, namely alteration of cell proliferation, cel l differentiation, programmed cell death (apoptosis) or adaptive responses of differentiated cells. (C) 2000 Wiley-Liss. Inc.