Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Immune-System Cells May Promote Chronic Infections

03.06.2005


Cells sent to fight infections in the lungs of cystic fibrosis patients actually enhance the development of permanent bacterial infections, according to researchers at National Jewish Medical and Research Center. Infections with the bacteria Pseudomonas are a major cause of sickness and death in cystic fibrosis patients. The findings, published in the June issue of Infection and Immunity, suggest new treatment strategies for patients with cystic fibrosis.



"Pseudomonas can use the remnants of dead white blood cells to develop a protective biofilm, which helps the bacteria establish a permanent infection," said National Jewish pulmonologist Jerry Nick, M.D., senior author on the paper. "So, ironically, the very cells sent to fight infection may contribute to our inability to eradicate the Pseudomonas infection in cystic fibrosis patients."

Cystic fibrosis (CF) is a genetic disorder affecting about 30,000 people in the United States, and is the most common genetic disorder among Caucasian people. People with CF produce abnormal mucus that obstructs the airways and leads to chronic lung infections. The disease is fatal, but life expectancy for patients has increased dramatically in recent years, from 14 years in the mid-1980s to 35 years today. National Jewish has one of the largest adult cystic fibrosis clinics in the nation.


Pseudomonas aeruginosa is widespread in the environment and repeatedly infects most CF patients. Aggressive treatment with antibiotics successfully fights most initial infections. Over time, however, P. aeruginosa infections often become permanent; more than 80% of adults with CF are chronically infected with P. aeruginosa. The chronic infection and inflammation associated with P. aeruginosa accelerate damage to the lungs, leading ultimately to respiratory failure and death.

Researchers believe that Pseudomonas establishes a chronic infection in the airway of CF patients by creating a biofilm, a three-dimensional structure composed of bacteria encased in an extracellular matrix. Other examples of bacterial biofilms include the plaque that forms on teeth and the "slime" that forms on rocks in a stream. Bacteria in biofilms take on distinctly different characteristics from those floating free in a "planktonic" form. Once Pseudomonas develops a biofilm it becomes significantly more resistant to both antibiotics and the immune system.

The immune system attempts to eradicate Pseudomonas by sending in massive numbers of cells called neutrophils. The short-lived cells die after a short time and cellular debris accumulate in the airway of CF patients.

In a series of experiments with neutrophils and Pseudomonas, Dr. Nick and his colleagues found that the contents of dead neutrophils, particularly DNA and a filament called actin, provide a scaffolding for Pseudomonas to construct a biofilm. In the presence of neutrophils, the development of P. aeruginosa biofilms increased by two and a half to three times compared to P. aeruginosa cultures without neutrophils.

"As the neutrophils die and fall apart, their contents provide an excellent substrate for the development of biofilms," said Nick. "In turn these biofilms allow Pseudomonas to survive despite intense medical treatment."

The researchers also found that an enzyme known as DNase, which breaks apart strands of DNA, inhibits the development of biofilms. DNase is already used to break up the thick mucus that develops in the lungs of CF patients. Nick believes that it might also be useful in preventing the development of Pseudomonas biofilms.

"Once the biofilm develops, Pseudomonas infections become almost impossible to eradicate," said Nick. "If we could prevent the development of these biofilms, with DNase or other treatments, we could possibly prevent chronic infections, reduce damage to the lungs of cystic fibrosis patients, and extend their lives."

Dr. Nick and his group are now using genomic analysis to better understand how the presence of neutrophils changes the response of Pseudomonas. They hope to discover mechanisms Pseudomonas uses to avoid eradication by the immune system, which could suggest new therapies to prevent Pseudomonas infections from developing in CF patients.

William Allstetter | EurekAlert!
Further information:
http://www.njc.org

More articles from Life Sciences:

nachricht Scientists enlist engineered protein to battle the MERS virus
22.05.2017 | University of Toronto

nachricht Insight into enzyme's 3-D structure could cut biofuel costs
19.05.2017 | DOE/Los Alamos National Laboratory

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

Im Focus: Bacteria harness the lotus effect to protect themselves

Biofilms: Researchers find the causes of water-repelling properties

Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...

Im Focus: Hydrogen Bonds Directly Detected for the First Time

For the first time, scientists have succeeded in studying the strength of hydrogen bonds in a single molecule using an atomic force microscope. Researchers from the University of Basel’s Swiss Nanoscience Institute network have reported the results in the journal Science Advances.

Hydrogen is the most common element in the universe and is an integral part of almost all organic compounds. Molecules and sections of macromolecules are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

Innovation 4.0: Shaping a humane fourth industrial revolution

17.05.2017 | Event News

Media accreditation opens for historic year at European Health Forum Gastein

16.05.2017 | Event News

 
Latest News

New approach to revolutionize the production of molecular hydrogen

22.05.2017 | Materials Sciences

Scientists enlist engineered protein to battle the MERS virus

22.05.2017 | Life Sciences

Experts explain origins of topographic relief on Earth, Mars and Titan

22.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>