Featured Research

from universities, journals, and other organizations

Why obese people have higher rates of asthma

Date:
January 8, 2013
Source:
Columbia University Medical Center
Summary:
A new study has found that leptin, a hormone that plays a key role in energy metabolism, fertility, and bone mass, also regulates airway diameter. The findings could explain why obese people are prone to asthma and suggest that medications that increase leptin-signaling may relieve asthma in obese people.

A new study led by Columbia University Medical Center (CUMC) researchers has found that leptin, a hormone that plays a key role in energy metabolism, fertility, and bone mass, also regulates airway diameter. The findings could explain why obese people are prone to asthma and suggest that body weight-associated asthma may be relieved with medications that inhibit signaling through the parasympathetic nervous system, which mediates leptin function.

The study, conducted in mice, was published in the online edition of the journal Cell Metabolism.

"Our study started with the clinical observation that both obesity and anorexia can lead to asthma," said Gerard Karsenty MD, PhD, professor and chair of genetics and development and professor of medicine at CUMC, and lead author of the study. "This led us to suspect that there must be a signal coming from fat cells that somehow affects the lungs -- directly or indirectly." The most likely candidate was leptin, a protein made by fat cells that circulates in the bloodstream and travels to the brain.

Extensive evidence shows that obesity can cause narrowing of the airways (bronchoconstriction). When obesity develops in people with asthma, it exacerbates the breathing disorder and hampers its treatment through mechanisms that are poorly understood. The current study was designed to elucidate the genetic and molecular bases of the relationships among obesity, airway diameter, and lung function.

Through mouse studies, the researchers showed that abnormally low or high body weight and fat mass results in bronchoconstriction and diminished lung function. Next, they showed that leptin increases airway diameter independently of, and at a lower threshold than, its regulation of appetite.

Leptin affects the airways by decreasing the activity of the parasympathetic nervous system, a branch of the autonomic nervous system not usually associated with leptin. The researchers also showed that regulation of airway diameter occurs regardless of local inflammation in the bronchi.

The researchers conducted two subsequent experiments to determine if these findings might have bearing on asthma therapy. In one, they took obese, asthmatic mice and administered a substance that increases lung inflammation. When they infused leptin in the brain of these mice for four days, "There was no effect on inflammation, but airway diameter and lung functions were normal," said Dr. Karsenty. "This showed that, at least in the mouse, you can cure obesity-related asthma without affecting inflammation." In the second experiment, the researchers treated obese, asthmatic mice with drugs that decrease parasympathetic tone, or rate of neuronal firing. Again, the asthma abated after several days.

"The therapeutic implication is that it may be possible to correct asthma in obese people with drugs that inhibit parasympathetic signaling -- and thereby increase leptin-related brain signaling," said Dr. Karsenty. Such drugs are already available. One is tiotropium bromide. Clinical trials are needed before this or a more active and selective drug can be recommended for the treatment of body weight-associated asthma, Dr. Karsenty added.

The study was supported by the John M. Driscoll, Jr., MD, Children's Fund Scholars, the Irving Institute/Clinical Trials Office Pilot Award, and the National Institutes of Health (RO1 DK58883).


Story Source:

The above story is based on materials provided by Columbia University Medical Center. Note: Materials may be edited for content and length.


Journal Reference:

  1. Emilio Arteaga-Solis, Tiffany Zee, Charles W. Emala, Charles Vinson, Jόrgen Wess, Gerard Karsenty. Inhibition of Leptin Regulation of Parasympathetic Signaling as a Cause of Extreme Body Weight-Associated Asthma. Cell Metabolism, Jan 2013 DOI: 10.1016/j.cmet.2012.12.004

Cite This Page:

Columbia University Medical Center. "Why obese people have higher rates of asthma." ScienceDaily. ScienceDaily, 8 January 2013. <www.sciencedaily.com/releases/2013/01/130108122438.htm>.
Columbia University Medical Center. (2013, January 8). Why obese people have higher rates of asthma. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2013/01/130108122438.htm
Columbia University Medical Center. "Why obese people have higher rates of asthma." ScienceDaily. www.sciencedaily.com/releases/2013/01/130108122438.htm (accessed October 23, 2014).

Share This



More Health & Medicine News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Fears Keep Guinea Hospitals Empty

Ebola Fears Keep Guinea Hospitals Empty

AP (Oct. 23, 2014) — Fears of Ebola are keeping doctors and patients alike away from hospitals in the West African nation of Guinea. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Working Mother (Oct. 22, 2014) — Is your child ready? Video provided by Working Mother
Powered by NewsLook.com
U.S. Issues Ebola Travel Restrictions, Are Visa Bans Next?

U.S. Issues Ebola Travel Restrictions, Are Visa Bans Next?

Newsy (Oct. 22, 2014) — Now that the U.S. is restricting travel from West Africa, some are dropping questions about a travel ban and instead asking about visa bans. Video provided by Newsy
Powered by NewsLook.com
More People Diagnosed With TB In 2013, But There's Good News

More People Diagnosed With TB In 2013, But There's Good News

Newsy (Oct. 22, 2014) — The World Health Organizations says TB numbers rose in 2013, but it's partly due to better detection and more survivors. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins