Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Researchers show how air pollution can cause heart disease

21.12.2005


New York University School of Medicine researchers provide some of the most compelling evidence yet that long-term exposure to air pollution--even at levels within federal standards--causes heart disease. Previous studies have linked air pollution to cardiovascular disease but until now it was poorly understood how pollution damaged the body’s blood vessels.



In a well-designed mouse study, where animals breathed air as polluted as the air in New York City, the researchers pinpointed specific mechanisms and showed that air pollution can be particularly damaging when coupled with a high-fat diet, according to new research published in the December 21 issue of JAMA.

"We established a causal link between air pollution and atherosclerosis," says Lung Chi Chen, Ph.D., Associate Professor of Environmental Medicine at NYU School of Medicine and a lead author of the study. Atherosclerosis--the hardening, narrowing, and clogging of the arteries--is an important component of cardiovascular disease.


The study, done in collaboration with the Mount Sinai School of Medicine and University of Michigan, looked at the effects of airborne particles measuring less than 2.5 microns, referred to as PM2.5, the size linked most strongly with cardiovascular disease. The emissions arise primarily from power plants and vehicle exhaust. The US Environmental Protection Agency (EPA) has regulated PM2.5 since 1997, limiting each person’s average exposure per year to no more than 15 micrograms per cubic meter. These tiny particles of dust, soot, and smoke lead to an estimated 60,000 premature deaths every year in the United States.

Dr. Chen and his colleagues divided 28 mice, which were genetically prone to developing cardiovascular disease, into two groups eating either normal or high-fat diets. For the next six months, half of the mice in each feeding group breathed doses of either particle-free filtered air or concentrated air containing PM2.5 at levels that averaged out to 15.2 micrograms per cubic meter. This amount is within the range of annual EPA limits and equivalent to air quality in urban areas such as New York City.

The researchers then conducted an array of tests to measure whether the PM2.5 exposure had any impact on the mice’s cardiovascular health. Overall, mice who breathed polluted air fared worse than those inhaling filtered air. But when coupled with a high-fat diet, the impact of PM2.5 exposure was even more dramatic. The results added up to a clear cause and effect relationship between PM2.5 exposure and atherosclerosis, according to the study.

On the whole, mice breathing polluted air had far more plaque than those breathing filtered air. In cross sections taken from the largest artery in the body--the aorta--mice on normal diets and exposed to PM2.5 had arteries 19.2 percent filled with plaque, the fatty deposits that clog arteries. The arteries of those breathing particle-free air were 13.2 percent obstructed. Among high-fat diet mice, those exposed to PM2.5 had arteries that were 41.5 percent obstructed by plaque, whereas the arteries of the pollution-free mice were 26.2 percent clogged. In both normal and high-fat diet mice, PM2.5 exposure increased cholesterol levels, which are thought to exacerbate plaque buildup.

Though findings for increased plaque among mice eating normal diets were not statistically significant, Dr. Chen believes that future research on larger numbers of animals will solidify the trend. "Even with the low-fat diet, there’s still something there. So that is something to think about," he says. He suspects that PM2.5 exposure could also greatly affect even people who do not eat high-fat diets.

Mice exposed to PM2.5 also appeared prone to developing high blood pressure, another element of cardiovascular disease, because their arteries had become less elastic. To measure tension in the arteries, the researchers tested how the neurotransmitters serotonin and acetylcholine affected the aortic arches of PM2.5-exposed mice differently than those of controls. The arteries taken from exposed mice were less elastic than the control group, constricting more in the presence of serotonin and relaxing less in response to acetylcholine. Once again, the mice fed high-fat diets suffered the most pronounced effects from breathing polluted air.

Finally, the researchers also examined various measures of vascular inflammation, which is involved in atherosclerosis on a number of levels. In the aortas of PM2.5–exposed mice, for example, they found increased levels of macrophages, immune cells that are an important ingredient in plaque deposits and also active participants in a biochemical pathway related to inflammation. The study revealed several signs that this pathway was more active, strengthening the connection between airborne particles and cardiovascular disease.

Jennifer Choi | EurekAlert!
Further information:
http://www.nyumc.org

More articles from Health and Medicine:

nachricht Vanishing capillaries
23.03.2017 | Technische Universität München

nachricht How prenatal maternal infections may affect genetic factors in Autism spectrum disorder
22.03.2017 | University of California - San Diego

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>