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 How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>