Navigation Links
Infection blocks lung's protective response against tobacco smoke
Date:8/19/2008

An infection that often goes undetected can block the lung's natural protective response against tobacco smoke, according to researchers at National Jewish Health. The findings, recently published online and scheduled to appear in the October issue of Infection and Immunity, suggest one mechanism that may cause smokers to develop chronic obstructive pulmonary disease.

"Although smoking is the overwhelming cause of chronic obstructive pulmonary disease (COPD), only 20 percent of smokers develop the disease," said Brian Day, senior author on the study and Professor of Medicine at National Jewish Health. "Our findings suggest that Mycoplasma pneumoniae (Mp) infection may be one of the co-factors that lead to COPD and other diseases among smokers."

Tobacco smoke contains more than 4,700 chemicals, which generate approximately 100 trillion reactive molecules per puff. Those molecules, known as reactive species, can damage lung tissue by chemically reacting with DNA, cell membranes and other molecules in the lung.

It has long been known that the lungs mount a strong protective response against tobacco smoke, which the National Jewish researchers confirmed in their studies in mice and cell cultures. They found that mice exposed to tobacco smoke for 16 weeks doubled the amount of the antioxidant glutathione in the fluid bathing the airways. The antioxidant reacts with the reactive species in tobacco smoke, thus preventing damaging reactions with lung tissue.

"This natural protective response actually allows people to smoke," said Day. "Without it, all smokers would suffer significantly more lung damage."

Previous work in Dr. Day's lab had suggested that lung infections might affect the lung's protective response. And work in Dr. Richard Martin's lab at National Jewish has implicated the organism Mycoplasma pneumoniae (Mp) in worsening asthma. Mp is a common lung pathogen and the most common cause of pneumonia, but can be difficult to detect because it is challenging to grow in culture. Recent tests to detect Mp DNA in the lungs have indicated that it may be more prevalent than generally recognized and can exist as a low-level chronic infection.

When Dr. Day and his colleagues infected mice with Mp it had a mild effect, slightly lowering glutathione levels in the lungs of mice breathing fresh air. When mice were exposed to tobacco smoke then infected with Mp, glutathione levels dropped even lower.

"The Mycoplasma infection completely blocked the protective response mice normally mount against tobacco smoke, reducing antioxidant levels well below even those of mice breathing fresh air," said Dr. Day.

After glutathione reacts and neutralizes reactive species in the lungs, it becomes oxidized. Under normal conditions mice and humans produce an enzyme, called glutathione reductase (GR), which recycles the oxidized glutathione into its protective, reduced state.

The researchers found that mice exposed to tobacco smoke and Mp had much higher levels of oxidized glutathione along with the low levels of reduced glutathione. The researchers also found that the Mp infection significantly lowered levels of GR in mice lungs.

"The Mycoplasma infection blocked the lungs' protective response to tobacco smoke by lowering levels of the enzyme that normally recycles oxidized glutathione back into its protective, reduced form," said Dr. Day. "This resulted in severe oxidative stress and increased tissue damage as measured by oxidized DNA.

"These higher levels of oxidative stress and damage are likely to predispose smokers with Mycoplasma infections to lung disease, such as COPD or cancer."


'/>"/>

Contact: William Allstetter
allstetterw@njc.org
303-398-1002
National Jewish Medical and Research Center
Source:Eurekalert

Related biology news :

1. New step forward in search for solution to infection puzzle
2. Antimicrobial sutures reduce infections in brain shunt surgery, study finds
3. CMV infections affect more than just patients with compromised immune systems, researchers find
4. Control switches found for immune cells that fight cancer, viral infection
5. Study findings show infection control intervention helps keep kids in school
6. HIV infection stems from few viruses
7. Early treatment of stomach infection may prevent cancer
8. USC School of Dentistry researchers uncover link between osteoporosis drugs and jaw infection
9. Ugandan monkeys harbor evidence of infection with unknown poxvirus
10. Analysis of RNA role in spreading disease advances study of damaging plant infections
11. UC Davis researchers discover how HIV turns food-poisoning into lethal infection
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/28/2017)... , March 28, 2017 The ... Hardware (Camera, Monitors, Servers, Storage Devices), Software (Video Analytics, ... Region - Global Forecast to 2022", published by MarketsandMarkets, ... 2016 and is projected to reach USD 75.64 Billion ... and 2022. The base year considered for the study ...
(Date:3/24/2017)... 24, 2017 The Controller General of Immigration from ... Abdulla Algeen have received the prestigious international IAIR Award for the ... Continue Reading ... ... Controller Abdulla Algeen (small picture on the right) have received the IAIR ...
(Date:3/23/2017)... The report "Gesture Recognition and Touchless Sensing Market by Technology (Touch-based ... to 2022", published by MarketsandMarkets, the market is expected to be worth USD ... 2022. Continue Reading ... ... ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... and LAGUNA HILLS, Calif. , Oct. ... Cancer Research, London (ICR) and University ... SKY92, SkylineDx,s prognostic tool to risk-stratify patients with multiple myeloma ... MUK nine . The University of Leeds ... partly funded by Myeloma UK, and ICR will perform the ...
(Date:10/10/2017)... ... 2017 , ... San Diego-based team building and cooking events company, Lajollacooks4u, has ... The bold new look is part of a transformation to increase awareness, appeal to ... period. , It will also expand its service offering from its signature gourmet cooking ...
(Date:10/10/2017)... 10, 2017 International research firm Parks Associates announced ... at the TMA 2017 Annual Meeting , October 11 in ... residential home security market and how smart safety and security products impact ... Parks Associates: Smart Home ... "The residential security market has ...
(Date:10/9/2017)... DIEGO , Oct. 9, 2017  BioTech ... biological mechanism by which its ProCell stem cell ... critical limb ischemia.  The Company, demonstrated that treatment ... amount of limbs saved as compared to standard ... the molecule HGF resulted in reduction of therapeutic ...
Breaking Biology Technology: