Featured Research

from universities, journals, and other organizations

Cigarette Smoke May Alter Immune Response In COPD Exacerbations

Date:
April 14, 2009
Source:
American Thoracic Society
Summary:
Smoking cigarettes is not only the principle cause of chronic obstructive pulmonary disease, but it may change the body's immune responses to bacteria that commonly cause exacerbations of the disease, according to new research in a mouse model.

Smoking cigarettes is not only the principle cause of chronic obstructive pulmonary disease (COPD), but it may change the body's immune responses to bacteria that commonly cause exacerbations of the disease, according to new research in a mouse model.

Related Articles


"It is well established that smoking is the main risk factor for COPD. But our research also suggests that cigarette smoke substantially changes the immune response to bacteria, which means that patients with COPD who smoke are weakening their body's ability to deal effectively with bacterial invaders. This may cause even further progression of the disease," said Martin Stämpfli, Ph.D., an associate professor at McMaster University, the principle investigator of the study.

"We wanted to see whether and how cigarette smoke would change the inflammatory response to the bacteria that is the culprit behind many COPD exacerbations, nontypeable Haemophilus influenzae or NTHI."

Their results were published in the second issue of April of the American Journal of Respiratory and Critical Care Medicine.

Dr. Stämpfli and colleagues tested the effects of cigarette smoke exposure on inflammation and immune response in mice that were exposed to cigarette smoke twice daily five days a week for either eight weeks or four days then challenged with an intranasal inoculation of NTHI. The cigarette smoke exposure roughly approximated that of an "average" human smoker (within the limitations of a model with differing metabolic processes.) Control mice were not exposed to cigarette smoke, but were inoculated with NTHI as were the cigarette smoke-exposed mice.

The researchers found that mice that were exposed to cigarette smoke, whether for four days or for eight weeks, showed distinct shifts in their immune-response profile, namely an increase in inflammation of the lungs after the NTHI challenge, increased weight-loss in response to the bacterial infection and, notably, a shift in the expression of inflammatory markers.

"Many interventions are developed with a homeostatic model in mind," said Dr. Stämpfli. "However, if our findings are borne out in clinical research, they would indicate that treatment targets for smokers with COPD may be markedly different than in non-smokers. Smoking may change the underlying inflammatory pathways elicited after bacterial infection."

Because of the shift in the inflammatory profile, the researchers wondered if it would have an effect on the efficacy of treatment with the usual corticosteroids.

Interestingly, they found that while the corticosteroid dexamethasone was effective in controlling the inflammation following bacterial challenge in both control and cigarette smoke-exposed mice, but it appeared to compromise the body's ability to clear the bacteria from the lungs.

"This was true for both control- and cigarette smoke-exposed mice and raises questions about the long-term use of corticosteroids in COPD. Certainly, there is evidence that corticosteroid treatment reduces the number of exacerbations in patients with COPD. This, however, is associated with occurrence of pneumonia, which is mirrored by our results. Therefore, inflammation is not altogether bad in the context of a bacterial infection, as it is required to clear the bacteria. It is the excessive inflammation observed in smokers that is of concern, as it may lead to lung damage."

The researchers note that the NTHI bacterium is an obligate human pathogen, and therefore an imperfect fit for a mouse model of COPD. "In the context of this present study, NTHI challenge was used as a tool to address the hypothesis of cigarette smoke exposure on the ensuing inflammatory response, and may not be perfectly suited to address pulmonary clearance, as a mouse-adapted pathogen may demonstrate different kinetics of clearance," Dr. Stämpfli noted.

Dr. Stämpfli intends to focus future research on detailing the precise immunological changes elicited by cigarette smoke exposure. "We must have a better understanding of which inflammatory markers are changing and how in order to develop a better understanding of potential targets for interventions," he said.

The research was supported in part by the Canadian Institutes of Health Research (CIHR).


Story Source:

The above story is based on materials provided by American Thoracic Society. Note: Materials may be edited for content and length.


Cite This Page:

American Thoracic Society. "Cigarette Smoke May Alter Immune Response In COPD Exacerbations." ScienceDaily. ScienceDaily, 14 April 2009. <www.sciencedaily.com/releases/2009/04/090407074951.htm>.
American Thoracic Society. (2009, April 14). Cigarette Smoke May Alter Immune Response In COPD Exacerbations. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2009/04/090407074951.htm
American Thoracic Society. "Cigarette Smoke May Alter Immune Response In COPD Exacerbations." ScienceDaily. www.sciencedaily.com/releases/2009/04/090407074951.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

From Popcorn To Vending Snacks: FDA Ups Calorie Count Rules

Newsy (Nov. 25, 2014) — The US FDA is announcing new calorie rules on Tuesday that will require everywhere from theaters to vending machines to include calorie counts. Video provided by Newsy
Powered by NewsLook.com
Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Daily Serving Of Yogurt Could Reduce Risk Of Type 2 Diabetes

Newsy (Nov. 25, 2014) — Need another reason to eat yogurt every day? Researchers now say it could reduce a person's risk of developing type 2 diabetes. Video provided by Newsy
Powered by NewsLook.com
Madagascar Working to Contain Plague Outbreak

Madagascar Working to Contain Plague Outbreak

AFP (Nov. 24, 2014) — Madagascar said Monday it is trying to contain an outbreak of plague -- similar to the Black Death that swept Medieval Europe -- that has killed 40 people and is spreading to the capital Antananarivo. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com
Are Female Bosses More Likely To Be Depressed?

Are Female Bosses More Likely To Be Depressed?

Newsy (Nov. 24, 2014) — A new study links greater authority with increased depressive symptoms among women in the workplace. 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