July 28, 2007
Diesel Particulates Plus Cholesterol Equals Inflammation

Diesel particulate pollution works synergistically with cholesterol to increase gene expression for genes involved in inflammation.

Got high cholesterol? You might want to stay away from air pollution.

That's the message of a new UCLA study linking diesel exhaust to atherosclerosis, or hardening of the arteries, which significantly increases one's risk for heart attack and stroke. Published in the July 26 edition of the online journal Genome Biology, the findings are the first to explain how fine particles in air pollution conspire with artery-clogging fats to switch on the genes that cause blood vessel inflammation and lead to cardiovascular disease.

"When you add one plus one, it normally totals two," said principal investigator Dr. André Nel, chief of nanomedicine at the David Geffen School of Medicine at UCLA and a researcher at UCLA's California NanoSystems Institute. "But we found that adding diesel particles to cholesterol fats equals three. Their combination creates a dangerous synergy that wreaks cardiovascular havoc far beyond what's caused by the diesel or cholesterol alone."

At the moment a battle is raging in Sacramento about a regulatory change to require construction companies and other operators of off-road diesel equipment to gradually upgrade or retire diesels that emit lots of particulates and other pollutants. The emissions restrictions for diesel cars are much tougher than the restrictions for off-road equipment. Well, diesel pollutants really are bad for human health and the polluters have been allowed to pollute for far too long.

Cells from human blood vessels were exposed to diesel particulates and

"Diesel particles are coated in chemicals containing free radicals, and the fatty acids in LDL cholesterol generate free radicals during metabolism in the cells," said first author Ke Wei Gong, a UCLA cardiology researcher. "We wanted to measure what happens when these two sources of oxidation come into contact."

The scientists combined the pollutants and oxidized fats and cultured them with cells from the inner lining of human blood vessels. A few hours later, the team extracted DNA from the cells for genetic analysis.

"We saw that the diesel particles and oxidized fats had worked in tandem to activate the genes that promote cellular inflammation — a major risk factor for atherosclerosis," said Dr. Jesus Araujo, UCLA assistant professor of medicine and director of environmental cardiology at the Geffen School of Medicine.

"The interaction left a genetic footprint that reveals how interaction between the particles and cholesterol accelerates the narrowing and blockage of the blood vessels," Araujo noted.

Now you might be saying that cell culture studies often do not reflect what happens in whole organisms. True enough. But these scientists saw similar gene expression changes when they repeated the experiment with live mice.

To duplicate these findings in living cells, the UCLA team exposed mice with high cholesterol to the diesel particles and saw activation of some of the same gene groups in the animals' tissue.

Do not live near highways. Do not live in areas with high levels of air pollution. If you must then consider installing a particulate air filter.

Share |      Randall Parker, 2007 July 28 09:30 PM  Health Pollution Harm

David Govett said at July 28, 2007 11:41 PM:

HEPA filters remove down to about 0.3 microns, but diesel particles can be as small as about 0.04 microns. The best solution is: exhale, don't inhale.

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