Symposium to Discuss Pollution-Heart Disease Link

Aruni Bhatnagar, Ph.D., of the University of Louisville and Robert Brook, Ph.D., of the University of Michigan have organized a symposium Environmental Factors in Heart Disease, to take place April 21 at the Experimental Biology conference in New Orleans.

The American Physiological Society is one of the sponsors of the annual conference.

Bhatnagar will speak on "Environmental Aldehydes Exposure and Cardiovascular Disease," while Brook will give a talk on "Environmental Pollution and Hypertension." In addition, Araujo Jesus of the University of California, Los Angeles, will speak on "Exacerbation of Experimental Atherogenesis by Ultrafine Air Pollution," and Murray Mittleman of the Harvard School of Public Health will speak on "Air Pollution and Stroke."

Several studies have connected pollution to heart disease:

  • A study of six U.S. cities found that people died earlier when they lived in cities with higher pollution levels. A majority of these deaths were due to heart disease.
  • A study of 250 metropolitan areas around the world found a spike in air pollution is followed by a spike in heart attacks.
  • A study in Salt Lake City found that when a nearby steel mill shut down for a period of months, there was a 4-6 percent drop in mortality. The mortality rose to previous levels when the steel mill reopened.

Researchers are trying to find out which pollutants are harmful and how the harmful pollutants work to damage the cardiovascular system. They have focused on smaller, microscopic particles that can get into the lungs and may gain entrance to the blood stream. (The upper airway filters out larger particles that are in smog and other air pollutants before they can cause a problem.)

In addition, researchers have focused on air pollutants, including ozone, nitrates, sulfates, metals, and aldehydes.

Bhatnagar has found that aldehydes—a toxic class of chemicals found in most forms of smoke, including cigarette smoke and car exhaust—increase blood cholesterol levels and activate enzymes that cause plaque in the blood vessels to rupture. When plaque ruptures, it can cause a blood clot, which may block an artery and lead to a heart attack.

Much of Brook's research has centered on the relationship between air pollution and hypertension. Fine- and ultra-fine particles that get into the lung may make their way into the blood vessels. Within 15 minutes of inhaling pollutants, there is a very rapid increase in blood pressure, he said.

Blood vessels react to the pollutants by producing an inflammatory response to attack the foreign matter. However, the inflammatory response itself can set off a complex physiological reaction that is harmful to the blood vessels, Brook said.

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