Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Probiotic protects intestine from radiation injury

17.11.2011
Scientists at Washington University School of Medicine in St. Louis have shown that taking a probiotic before radiation therapy can protect the intestine from damage — at least in mice.

The new study suggests that taking a probiotic also may help cancer patients avoid intestinal injury, a common problem in those receiving radiation therapy for abdominal cancers. The research is published online in the journal Gut.

Radiation therapy often is used to treat prostate, cervical, bladder, endometrial and other abdominal cancers. But the therapy can kill both cancer cells and healthy ones, leading to severe bouts of diarrhea if the lining of the intestine gets damaged.

"For many patients, this means radiation therapy must be discontinued, or the radiation dose reduced, while the intestine heals," says senior investigator William F. Stenson, MD, the Dr. Nicholas V. Costrini Professor in Gastroenterology & Inflammatory Bowel Disease at Washington University. "Probiotics may provide a way to protect the lining of the small intestine from some of that damage."

Stenson has been searching for ways to repair and protect healthy tissue from radiation. This study showed that the probiotic bacteria Lactobacillus rhamnosus GG (LGG), among other Lactobacillus probiotic strains, protected the lining of the small intestine in mice receiving radiation.

"The lining of the intestine is only one cell-layer thick," Stenson says. "This layer of epithelial cells separates the rest of the body from what's inside the intestine. If the epithelium breaks down as the result of radiation, the bacteria that normally reside in the intestine can be released, travel through the body and cause serious problems such as sepsis."

The researchers found that the probiotic was effective only if given to mice before radiation exposure. If the mice received the probiotic after damage to the intestinal lining had occurred, the LGG treatment could not repair it in this model.

Because the probiotic protected intestinal cells in mice exposed, the investigators believe it may be time to study probiotic use in patients receiving radiation therapy for abdominal cancers.

"In earlier human studies, patients usually took a probiotic after diarrhea developed when the cells in the intestine already were injured," says first author Matthew A. Ciorba, MD, assistant professor of medicine in the Division of Gastroenterology. "Our study suggests we should give the probiotic prior to the onset of symptoms, or even before the initiation of radiation because, at least in this scenario, the key function of the probiotic seems to be preventing damage, rather than facilitating repair."

The investigators sought to evaluate LGG's protective effects in a way that would leave little doubt about whether it was preventing injury, and if so, how it was protecting the cells that line the intestine.

"Some human studies have looked at the possibility that probiotics might reduce diarrhea, but most of those studies have not been quite as rigorous as we would like, and the mechanism by which the probiotics might work has not been addressed," Stenson says.

Previously, Stenson and his colleagues demonstrated that a molecular pathway involving prostaglandins and cyclooxygenase-2 (COX-2), key components in inflammation, could protect cells in the small intestine by preventing the programmed cell death, or apoptosis, that occurs in response to radiation.

They gave measured doses of LGG to mice, directly delivering the live bacteria to the stomach. They found it protected only mice that could make COX-2. In mutant mice unable to manufacture COX-2, the radiation destroyed epithelial cells in the intestine, just as it did in mice that didn't receive the probiotic.

"In the large intestine, or colon, cells that make COX-2 migrate to sites of injury and assist in repair," Ciorba says. "In this study, we evaluated that response in the small intestine, and we found that COX-2-expressing cells could migrate from the lining to the area of the intestine, called the crypt, where new epithelial cells are made, and we believe this mechanism is key to the protective effect we observed."

If human studies are launched, Ciorba says one bit of encouraging news is that the doses of probiotic given to mice were not exceptionally large, and their intestines were protected. So people wouldn't need mega-doses of the probiotic to get protection.

"The bacteria we use is similar to what's found in yogurt or in commercially available probiotics," he says. "So theoretically, there shouldn't be risk associated with this preventative treatment strategy any more than there would be in a patient with abdominal cancer eating yogurt."

In addition, he notes, future research is focused on isolating the particular radio-protective factor produced by the probiotic. When that is identified, a therapeutic could be developed to harness the probiotic benefit without using the live bacteria.

Ciorba MA, Riehl TE, Rao SM, Moon C, Ee X, Nava GM, Walker MS, Marinshaw JM, Stappenbeck TS, Stenson WF. Lactobacillus probiotic protects intestinal epithelium from radiation injury in a TLR2/cyclo-osygenase-2-dependent manner. Gut, available online at http://gut.bmj.com/content/early/2011/10/24/gutjnl-2011-300367.long

Funding for this research comes from the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health (NIH), the Crohn's and Colitis Foundation of America and a Global Probiotics Council Young Investigator Award given to Matthew A. Ciorba, MD.

Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked fourth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.

Jim Dryden | EurekAlert!
Further information:
http://www.wustl.edu

More articles from Health and Medicine:

nachricht Building blocks for new medications: the University of Graz is seeking a technology partner
19.03.2019 | Karl-Franzens-Universität Graz

nachricht Scientists find new approach that shows promise for treating cystic fibrosis
14.03.2019 | NIH/National Heart, Lung and Blood Institute

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

Im Focus: Revealing the secret of the vacuum for the first time

New research group at the University of Jena combines theory and experiment to demonstrate for the first time certain physical processes in a quantum vacuum

For most people, a vacuum is an empty space. Quantum physics, on the other hand, assumes that even in this lowest-energy state, particles and antiparticles...

Im Focus: Sussex scientists one step closer to a clock that could replace GPS and Galileo

Physicists in the EPic Lab at University of Sussex make crucial development in global race to develop a portable atomic clock

Scientists in the Emergent Photonics Lab (EPic Lab) at the University of Sussex have made a breakthrough to a crucial element of an atomic clock - devices...

Im Focus: Sensing shakes

A new way to sense earthquakes could help improve early warning systems

Every year earthquakes worldwide claim hundreds or even thousands of lives. Forewarning allows people to head for safety and a matter of seconds could spell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Levitating objects with light

19.03.2019 | Physics and Astronomy

New technique for in-cell distance determination

19.03.2019 | Life Sciences

Stellar cartography

19.03.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>