As if making the air stink and harder to breathe wasn’t enough, researchers in Italy and Boston have found that when certain particulates from traffic exhaust increase, epigenetic effects can increase. They looked at the percent of methylated cytosines in Long Interspersed Nucleotide Elements (LINE-1) repeats, in leukocytes of elderly men taking part in a longitudinal study. When these numbers were plotted against local ambient black carbon- and PM2.5 (particulates ≤2.5 μ in diameter)-level readings, the correlation of pollutant levels to the drop in LINE-1 methylation was significant.
It’s expected that hypomethylation of LINE-1 repetitive sequences will likely lead to an increase in its transcriptional activation, something which has been linked to heart disease. And, with about ½ million of these repeats per cell, methylation has been seen to correlate that of the genome as a whole. For all the toxic details, take a deep breath and go to Am. J. Respir. Crit. Care Med., January 2009.