Heavy metals of relevance to human health induce genomic instability

Heavy metals used in medical prostheses or present in water supplies or tob acco can build up in tissues and blood and are well known to produce toxic effects. Normally, legislative controls on the levels of these substances a re determined by reference to the acute toxicity data. This paper shows tha t cadmium and nickel can produce delayed effects in human cells in vitro, w hich are characteristic of genomic instability. The effects occur even at l evels where no acute toxic effects can be demonstrated. Genomic instability can be demonstrated by persistent induction of cytogenetic abnormalities a nd delayed cell death in progeny of cells many generations after exposure. Formerly, this syndrome has only been definitively proven to occur followin g irradiation, but in these experiments cell populations exposed for only 1 or 24 hours were expanded over several months, involving eight passages, a nd the yield of chromosomal aberrations and cell loss due to lethal mutatio ns did not decrease. The consequences of this genomic instability are not y et known but it is possible that many of the systemic symptoms associated w ith exposure to low concentrations of these metals could involve delayed ex pression of cellular damage. It is also clear that these effects cannot be predicted from acute toxicity data. Copyright (C) 2001 John Wiley & Sons, L td.