NEW YORK, Sept. 6 (UPI) -- Radiation can damage or kill cells in human tissue that have not been directly exposed to radiation, say researchers at Columbia University.
The scientists from the school's Center for Radiological Research said such "bystander" tissue can be located up to 1 millimeter away from irradiated cells and, while the distance is too small to be an issue for radiotherapy, it may potentially increase risks associated with low-dose radiation.
David Brenner and colleagues induced highly localized radiation damage in a three-dimensional model of human skin. After irradiation of a small, well-defined section of tissue, unirradiated cells 1 millimeter away displayed biological responses. The researchers said such responses included the appearance of chromosome fragments, indicative of DNA damage, as well as programmed cell death.
Brenner said the surprisingly long range of the bystander effects suggests cells damaged by radiation may release chemical signals into surrounding tissue, or possibly a cell relay system transmits information about radiation damage over relatively long distances.
The research appears in this week's early online edition of the Proceedings of the National Academy of Sciences