Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bacteria get off easy in sinus infections

18.09.2006
Weakened immune system in chronic sinusitis reveals new treatment targets

Researchers at Johns Hopkins have evidence that curbed activity from several key chemicals on the inner lining of the nose are linked to chronic sinusitis that fails to respond to the usual current treatments.

An estimated 32 million Americans know the misery of persistent inflammation of the moist tissue that lines the nose and sinus cavities. The result is clogged passages and recurring infections, according to the U.S. Centers for Disease Control and Prevention.

Because nearly one in 10 of those treated see symptoms return within weeks or months after drugs or surgery fail to keep the sinus passages open, scientists have long suspected that these resistant cases had some underlying problem with the immune system contributing to the ailment.

... more about:
»Chronic »TLR »inflammation »polyps »receptor »sinusitis

In a study to be described on Sept. 19 at the annual scientific sessions of the American Academy of Otolaryngology, Head and Neck Surgery, the Hopkins team found that in chronic sufferers who failed to respond to treatment, the activity of at least four genes in the body's nasal immune defense system were severely decreased, and their production of two proteins critical to this defense was 20 to 200 times less than normal.

Comparing nasal epithelial cell samples from nine patients who benefited from surgery with nine who did not, the Hopkins team discovered suppressed levels of human beta defensin 2 (HBD2) and mannose binding lectin (MBL) in those whose symptoms returned. The proteins are naturally produced in the nose whenever the immune system detects foreign bacteria or fungi, binding to invading pathogens, inactivating them and making them easily disposed of.

An earlier study published by the same team in the March-April issue of the American Journal of Rhinology also showed that sinus tissue from people with chronic sinusitis that resisted treatment had 30 times lower than normal activity of a so-called toll-like receptor gene, TLR9.

Inside the nose, researchers say, toll-like receptor proteins (TLRs) detect invading bacteria and other pathogens in the air by attaching to their trace byproducts. Once a threat is identified, the receptors stimulate the epithelial cells to produce antibiotic proteins, such as HBD2 and MBL, to fight the invading organisms. This innate response helps prevent airborne bacteria or fungi from settling in the nose and sinus cavities, causing infection.

"Colonization with microorganisms is a common problem in patients with chronic sinusitis and polyps, but the reasons for this are incompletely understood," says Andrew Lane, M.D., an associate professor at The Johns Hopkins University School of Medicine and director of its rhinology and sinus surgery center. "Now we are uncovering new clues as to what might be wrong and perhaps, ultimately, how it might be treated.

"The nose's first line of defense is the epithelium, and when the local innate immune function is curtailed, infections can get a head start, which might serve to worsen the sinus inflammation.

"The potential is there to manipulate these chemical receptors and proteins to see if this makes patients more responsive to conventional therapy," says Lane.

The study, led by Lane, was believed to be the first to determine levels of each TLR - there are 10 - by directly measuring messenger RNA expression in sinusitis patients and those more fortunate to not have it. Scientists have known for more than a year that TLRs were present in both the healthy and sinusitis-wracked nose, but not which receptors or proteins were more important than others in the condition's chronic form. That study involved 30 men and women, mostly from the Baltimore region, who had surgery for chronic sinusitis at Hopkins. (Another 10 had no sinus problem and served as study controls.)

Those who underwent surgery did so after standard therapy using antibiotics, decongestants and steroids had failed to stop their symptoms and keep their infections from coming back. Indeed, 20 participants in the study had developed nasal polyps, which have no known cause and are especially hard to treat, researchers say. They note that polyps must often be surgically removed to allow the sinuses to drain normally.

All patients were monitored for a minimum of six months to see if any symptoms or polyps returned. Thirteen in the surgery group had recurrent inflammation within three months to one year after surgery, while the rest remained symptom free.

The Hopkins team took samples during surgery of the mucous membrane lining the nose, and using real-time polymerase chain reaction, analyzed the samples for any genetic differences between the groups.

"Surgically treating sinusitis is much like plumbing, in the sense that we try to restore normal sinus cavity drainage pathways," adds study presenter Murugappan Ramanathan Jr., M.D., a resident in otolaryngology - head and neck surgery at Hopkins. "But for the intractable cases, surgery may fail because the problem is not so much about plumbing as it is inflammation, and for this we need research at the molecular level to find a solution."

David March | EurekAlert!
Further information:
http://www.jhmi.edu

Further reports about: Chronic TLR inflammation polyps receptor sinusitis

More articles from Life Sciences:

nachricht Fungi that evolved to eat wood offer new biomass conversion tool
25.07.2017 | University of Massachusetts at Amherst

nachricht New map may lead to drug development for complex brain disorders, USC researcher says
25.07.2017 | University of Southern California

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA flights gauge summer sea ice melt in the Arctic

25.07.2017 | Earth Sciences

Fungi that evolved to eat wood offer new biomass conversion tool

25.07.2017 | Life Sciences

New map may lead to drug development for complex brain disorders, USC researcher says

25.07.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>