Though the existence of a direct link between diesel and cardiovascular disease is still unclear, scientists have known for a while that diesel particles — like low density lipoprotein (LDL), the bad form of cholesterol — can prompt the release of free radicals into blood vessels. Free radicals are a type of oxygen molecule that can harm human tissues. In the study, Andre Nel and his colleagues discovered that the combination of diesel particles and LDL cholesterol was especially effective at triggering genes known to harm tissue and prompt artery hardening, or atherosclerosis, in samples of human vascular tissue.
They then tested this in mice genetically engineered to have higher levels of cholesterol. After exposing them to one of three different environments — one with filtered air, the other with fine diesel particles and the last with both fine and intermediate-sized particles — they examined the animals' lungs and found that the diesel mice had the same level of damage and gene activation patterns as did the human tissue samples.
"This the first study to go so far into the biology behind the effect air pollutants have on the cardiovascular system. Most people figured there was something going on, but this gives us substantial evidence," said Stanlon Glantz, a toxicologist from the University of California, San Francisco. All the more reason to drop those diesel-guzzling cars.
Via ::ScienceNOW: Diesel: The Engine Behind Atherosclerosis? (news website)
See also: ::Ask TreeHugger: Are Exposures to Diesel Exhaust Related to My Heart Problems?, ::Converting Diesel Engines to Run on Vegetable Oil
Image courtesy of swinginstan via flickr