Navigation Links
Jekyll into Hyde: Breathing auto emissions turns HDL cholesterol from 'good' to 'bad'

Academic researchers have found that breathing motor vehicle emissions triggers a change in high-density lipoprotein (HDL) cholesterol, altering its cardiovascular protective qualities so that it actually contributes to clogged arteries.

In addition to changing HDL from "good" to "bad," the inhalation of emissions activates other components of oxidation, the early cell and tissue damage that causes inflammation, leading to hardening of the arteries, according to the research team, which included scientists from UCLA and other institutions.

The findings of this early study, done in mice, are available in the online edition of the journal Arteriosclerosis, Thrombosis and Vascular Biology, a publication of the American Heart Association, and will appear in the journal's June print edition.

Emission particles such as those from vehicles are major pollutants in urban settings. These particles are coated in chemicals that are sensitive to free radicals, which have been known to cause oxidation. The mechanism behind how this leads to atherosclerosis, however, has not been well understood.

In the study, the researchers found that after two weeks of exposure to vehicle emissions, mice showed oxidative damage in the blood and liver damage that was not reversed after a subsequent week of receiving filtered air. Altered HDL cholesterol may play a key role in this damaging process, they said.

"This is the first study showing that air pollutants promote the development of dysfunctional, pro-oxidative HDL cholesterol and the activation of an internal oxidation pathway, which may be one of the mechanisms in how air pollution can exacerbate clogged arteries that lead to heart disease and stroke," said senior author Dr. Jesus Araujo, an associate professor of medicine and director of environmental cardiology at the David Geffen School of Medicine at UCLA.

For the study, one group of mice was exposed to vehicle emissions for two weeks and then filtered air for one week, a second was exposed to two weeks of emissions with no filtered air, and a third was exposed to only clean, filtered air for two weeks. This part of the collaborative research took place at the Northlake Exposure Facility at the University of Washington, headed by study author Michael E. Rosenfeld.

"The biggest surprise was finding that after two weeks of exposure to vehicle emissions, one week of breathing clean filtered air was not enough to reverse the damage," said Rosenfeld, a professor of environmental and occupational health sciences and pathology at the University of Washington.

Mice were exposed for a few hours, several days a week, to whole diesel exhaust at a particulate mass concentration within the range of what mine workers usually are exposed to.

After the exposures, UCLA scientists analyzed blood and tissue specimens and checked to see if the protective antioxidant and anti-inflammatory properties of HDL, known as "good" cholesterol, were still intact. They used special analytical laboratory procedures originally developed by study author Mohamad Navab at UCLA to evaluate how "good" or "bad" HDL had become. The team found that many of the positive properties of HDL were markedly altered after the air-pollutant exposure.

For example, the HDL of mice exposed to two weeks of vehicle emissions, including those that received a subsequent week of filtered air, had a much-decreased ability to protect against oxidation and inflammation induced by low-density lipoprotein (LDL) cholesterol, known as "bad" cholesterol, than the mice that had only been exposed to filtered air.

According to researchers, without HDL's ability to inhibit LDL, along with other factors, the oxidation process may run unchecked. Moreover, not only was the HDL of the mice exposed to diesel exhaust unable to protect against oxidation, but, in fact, it further enhanced the oxidative process and even worked in tandem with the LDL to promote even more oxidative damage.

Researchers also found a twofold to threefold increase of additional oxidation products in the blood of mice exposed to vehicle emissions, as well as activation of oxidation pathways in the liver. The degree of HDL dysfunction was correlated with the level of these oxidation markers.

"We suggest that people try to limit their exposure to air pollutants, as they may induce damage that starts during the exposure and continues long after it ends," said first author Fen Yin, a researcher in the division of cardiology at the Geffen School of Medicine.

The current research builds on the team's previous findings that ambient ultrafine particles commonly found in air pollution, including vehicle emissions, enhance the build-up of cholesterol plaques in the arteries and that HDL may play a role.

"Our research helps confirm that the functionality of HDL may be as important to check as the levels," said study author Dr. Alan Fogelman, executive chair of the department of medicine and director of the atherosclerosis research unit at the Geffen School of Medicine.


Contact: Rachel Champeau
University of California - Los Angeles Health Sciences

Related medicine news :

1. Chef Jekyll Advises on Lunch at the Beach
2. Chef Jekyll to Show off Home-Grown Herbs at Second Annual Props, Wings and Wheels Extravaganza
3. Chef Jekyll to Be Featured at Second Annual Taste of North Bay
4. Many Americans Breathing Cleaner Air: Report
5. Bend, Oregon Resident Named to Board of Directors and Elected Vice-Chairman of Buteyko Breathing Educators Association
6. Breathing Problem Sometimes Misdiagnosed in Athletes
7. Spiro PD Personal Spirometer Helps People Track Their Breathing Disorders As Generally Mild Winter Signals Early Allergy Season
8. Dr. Steve Carstensen Presents First Webinar for Dental Division of American Sleep and Breathing Academy
9. Inserting Breathing Tube May Not Be Best for Victims of Cardiac Arrest
10. Treating sleep-disordered breathing in pregnancy may improve fetal health
11. Benefits of higher oxygen, breathing device persist after infancy
Post Your Comments:
(Date:10/12/2015)... ... October 13, 2015 , ... North American Tool Corporation ... the 2015 IBC National Meeting in Rosemont, IL on October 4th. ... and standards of excellence that customers have come to expect from members of IBC’s ...
(Date:10/12/2015)... ... ... Kevin Costello, winner of the “Check-In and Win a Vacation to Hawaii” Facebook contest at ... Hawaii. , “I didn’t believe I could win a free vacation simply by checking in ... to the gym and invest in my own health – and now I’m going to ...
(Date:10/12/2015)... Woodinville, WA (PRWEB) , ... October 12, 2015 , ... ... , a premier supplier of spa and skin care equipment, will be displaying custom ... October 19-21, 2015. , With many high-end resorts and spas as customers, SpaEquip is ...
(Date:10/12/2015)... ... October 12, 2015 , ... ... of hypnosis by individuals who lack professional education and clinical training in a ... public for a variety of purposes such as: losing weight, managing pain, or ...
(Date:10/12/2015)... ... October 12, 2015 , ... American Family Care (AFC), the ... footprint by opening its 151st medical center. Located at 606A Boll Weevil Circle in ... to continue fulfilling our mission of making quality health care accessible and economical with ...
Breaking Medicine News(10 mins):
(Date:10/12/2015)... , October 12, 2015 ... key insights on the global vital signs monitoring devices market ... Global Industry Analysis and Opportunity Assessment 2015-2025." The global vital ... healthy CAGR of 9.5% and 9.2% in terms of value ... regarding which FMI offers major insights in detail in this ...
(Date:10/12/2015)... , Oct. 12, 2015 Beginning October ... Codes. Therapy Partner, the fastest growing practice management system ... technology that easily converts all patient diagnostic codes from ... --> --> Therapy ... for all mental health practitioners to easily understand the ...
(Date:10/12/2015)... 12, 2015 Indivior PLC (LON: INDV) today announced ... Delaware granted the Company,s motion to amend ... Drug Application (ANDA) No. 205299 to market a generic equivalent ... Sublingual Film (CIII) in the United States ... August 2013, Indivior has received Paragraph IV certifications from six ...
Breaking Medicine Technology: