Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Common airborne substance makes asthmatics more sensitive to house dust mites: study

10.12.2003


Exposure to endotoxin, a bacterial substance found commonly in outdoor and indoor air, makes mite-allergic asthmatics more sensitive to house dust and may place them at increased risk of asthma attack.



The new research findings from the University of North Carolina at Chapel Hill School of Medicine are consistent with previous UNC studies showing exposure to ozone to make asthmatics more sensitive to allergens, the environmental triggers of allergic reactions. Both ozone and endotoxin are not allergens; however, they can cause portions of the respiratory tract to become inflamed.

The study is published this week in the online December issue of the Journal of Allergy and Clinical Immunology.


Endotoxin is a complex of lipids (fats) and sugar molecules that’s released through the outer cell wall of common bacteria. When the bacteria die, the cell wall collapses and endotoxin is released into the environment, finding its way into the air and dust.

"We know that asthmatics can have asthma attacks triggered by various environmental exposures, but we don’t always know why certain circumstances precipitate asthma attacks when there are no clear-cut exposures to the allergens they are sensitized to," said Dr. Brian A. Boehlecke, lead author of the report, professor of medicine in UNC’s pulmonary medicine division and member of UNC’s Center for Environmental Medicine, Asthma and Lung Biology.

"Now it appears that various airborne irritants such as ozone and endotoxin, which can cause airway inflammation, may interact synergistically with other causes of airway problems, including allergens, to make asthma worse," he said.

The new study involved 14 participants with mild asthma for whom skin testing showed allergies to house dust mites, one of the most common airborne allergens. Study participants inhaled relatively low levels of endotoxin over four hours that approximated those levels found in some homes and office buildings.

Following this exposure, participants underwent an "allergen challenge test." This inhalation test identifies the dose that causes their airways to constrict a specified degree. That dose, once determined for each person, is called their provocation dose, said study co-author Dr. Neil Alexis, assistant professor of pediatrics in the division of allergy, immunology and environmental medicine and a UNC center member.

"We found that when allergic individuals breathe endotoxin prior to their allergen challenge, they in fact became more sensitive to the allergen challenge. They were provoked at a lower concentration of allergen compared to previously inhaling air without endotoxin," he said.

The findings have implications for air pollution exposure, "in particular those pollutants that cause airway inflammation, which endotoxin does and which ozone does," Alexis said. "So in folks who are already allergic, if they are inhaling pollutants that can further exacerbate their inflammation, it may aggravate the symptoms they normally would have. In other words, they may experience a worsening of their symptoms."

Further UNC studies will examine if endotoxin, ozone and other airborne agents share common interactive mechanisms that may increase allergen sensitivity and disease severity in people with asthma.

"There is also the possibility of finding drugs to block that interaction and prevent the worsening of asthma," Boehlecke said. Along with Alexis and Boehlecke, UNC co-authors were Drs. Milan Hazucha, Robert Jacobs, Parker Reist, Philip A. Bromberg and David Peden.


Funding for the research came from the Center for Indoor Air Research and the National Institutes of Health.

Note: Contact Boehlecke at 919-966-2531 or boeh@med.unc.edu. Contact Alexis at 919-966-9915 or neil_alexis@med.unc.edu.

School of Medicine contact: Les Lang, 919-843-9687 or llang@med.unc.edu
News Services contact: Deb Saine, 919-962-8415 or deborah_saine@unc.edu

Leslie Lang | EurekAlert!
Further information:
http://www.med.unc.edu/

More articles from Studies and Analyses:

nachricht Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland

nachricht Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke

All articles from Studies and Analyses >>>

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 >>>