Air Pollution May Damage Brain, Heart

[Susan L Gawarecki <loc@icx.net>]

Just in case more evidence is needed to support increased reliance on

electricity from nuclear energy instead of coal-burning plants and

fossil-fuel vehicles....



--Susan Gawarecki



Air Pollution May Damage Brain, Heart 

April 16, 2003 04:02:35 PM PST, HealthScout News 



By Leonard Lee 

HealthScoutNews Reporter 



WEDNESDAY, April 16 (HealthScoutNews) -- Air pollution may cause brain

damage similar to Alzheimer's disease, as well as heart problems, two

new

studies suggest. Dogs exposed to air pollution were found to develop

damaged brain cell genes in as little as four weeks, according to

research presented April 15 at the Experimental Biology 2003 conference

in San Diego. 



The animals were exposed to the highly polluted air in different parts

of Mexico City, and compared against a control group of dogs kept in

less-polluted rural parts of Mexico. Mexico City is considered one of

the worst cities in the world for air pollution. 



More than 200 dogs were involved in the study, which lasted for more

than a year. The dogs in the highly polluted environment suffered lung

and upper

respiratory damage, which let particles enter the central nervous

system, leading to gene and DNA damage in their brain cells. Even dogs

less than 1 year old were found to have brain lesions similar to those

of human Alzheimer's patients, the researchers say. 



Lead researcher Dr. Lilian Calderon-Garciduenas, of the University of

North Carolina, says exposure to air pollution causes inflammation in

the respiratory tract, which lets tiny airborne particles and metals

enter the central nervous system and brain. This, in turn, causes

oxidative damage and DNA changes in brain cells. 



Air pollution breaks down the vital blood-brain barrier that usually

keeps toxic substances away from the brain, she says. "This is extremely

important," says Calderon-Garciduenas, "because once you break down the

barriers,you have an entrance for pollutants directly to your brain." 



The researchers also found signs of lung damage in children as young as

4 years old who were raised in Mexico City. "The same breakdown in the

respiratory system we're seeing in dogs is happening in children and

adults in Mexico City," Calderon-Garciduenas contends, "and it probably

also happens in cities like Los Angeles." 



A separate study presented at the same symposium found a link between

air pollution and heart problems in humans.  Exposure to air pollution

raised levels of certain peptides in the bloodstream that can constrict

blood vessels and decrease blood flow to the heart muscle, the

researchers found. 



The study was conducted at the Gage Institute of the University of

Toronto, where healthy volunteers were exposed to air pollution in a

laboratory setting. The volunteers were subjected to air pollution about

two to three times the level normally found in Toronto, which is

considered one of North America's less-polluted major cities. 



The study focused on endothelin, a naturally occurring peptide that

plays an important role in blood vessel health.  "If we expose healthy

humans to airborne particulates, we can document a doubling of

endothelin in the blood," says Renaud Vincent, one of the researchers

and head of Health Canada's Inhalation Toxicology and Aerobiology

Section. 



"We now have at least one mechanism that could plausibly explain how

someone with a heart condition exposed to a low level of air pollution

could die or come down with severe symptoms, such as congestive heart

failure," Vincent  says. 



Recent epidemiological studies have found higher rates of death and

hospitalization in cities with high levels of air pollution. Vincent

says the culprit appears to be airborne particulates. When test subjects

breathed polluted air for as little as two hours, the level of

vasoconstrictive peptides in their blood rose sharply and stayed at

abnormally high levels for as long as 24 hours, even without further

exposure. The changes in peptide levels were proportionate to the

concentration of particles to which the subjects were exposed. 



"The picture is starting to come together of why we see these spikes in

mortality associated with air pollution levels," says Fred Miller, a

researcher with CIIT Centers for Health Research, an independent,

non-profit research  organization based in North Carolina's Research

Triangle Park. "The mortality may be coming about because you have this

exposure, and how well can your system handle this added stressor?" he

says. 



Elevated levels of endothelin can reduce blood flow by as much as 50

percent, particularly in people with atherosclerosis, high blood

pressure and diabetes, Vincent says. Further study needs to be done on

which specific particulates and their components produce the rise in

vasoconstrictive peptide levels, he says. 



More information 



To learn more about the health risks posed by air pollution, visit: 



the Centers for Disease Control and Prevention 

http://www.cdc.gov/nceh/airpollution/ 



or the World Resources Institute. 

http://www.wri.org/wr-98-99/airpoll.htm 



or the Trust for America's Health 

http://www.healthyamericans.org 

--

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