Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Beneficial Bacteria Help Repair Intestinal Injury by Inducing Reactive Oxygen Species

11.05.2011
The gut may need bacteria to provide a little bit of oxidative stress to stay healthy, new research suggests.

Probiotic bacteria promote healing of the intestinal lining in mice by inducing the production of reactive oxygen species, researchers at Emory University School of Medicine have shown.

The results, published online this week in Proceedings of the National Academy of Sciences Early Edition, demonstrate a mechanism by which bacterial cultures in foods such as yogurt and kimchi have beneficial effects on intestinal health. The insights gained could also guide doctors to improved treatments for intestinal diseases, such as necrotizing enterocolitis in premature babies or intestinal injury in critically ill adults.

The laboratories of Andrew Neish, MD and Asma Nusrat, MD, both professors of pathology and laboratory medicine, teamed up for the study. The paper’s co-first authors are postdoctoral fellow Philip Swanson, PhD and associate research professor Amrita Kumar, PhD.

“It’s been known for years that probiotic bacteria can have these kinds of helpful effects, but it wasn’t really clear how this worked,” Neish says. “We’ve identified one example, among many, of how certain kinds of bacteria have specific biochemical functions in the body.”

Recent research has shown that the bacteria in our intestines influence our metabolism and immune systems. For example, an imbalance in the proportions of harmful and beneficial bacteria seems to over-activate immune cells in the intestines, driving inflammatory bowel disease.

Intestinal epithelial cells, the cells that line the intestine, live in close contact with bacteria and normally form a barrier that keeps bacteria away from other organs. They can repair small gaps in the barrier, which breaks down in intestinal diseases, by migrating into the gaps.

The researchers showed that Lactobacillus rhamnosus bacteria can accelerate this healing process, both in culture dishes and in mice with intestines damaged by chemicals. Lactobacillus rhamnosus, a species of bacteria found naturally in human intestines and often used as a probiotic, is a relative of other kinds of Lactobacillus bacteria found in fermented foods.

"Unlike most cell types that can not tolerate bacterial contact, intestinal epithelial cells respond to Lactobacillus rhamnosus by increasing their motility,” Neish says.

Using a fluorescent dye that is sensitive to reactive oxygen species (ROS), the researchers showed that intestinal epithelial cells produce ROS internally when in contact with Lactobacillus rhamnosus. The ROS induced by the bacteria stimulate the formation of focal adhesions, structures on intestinal epithelial cells that act as anchors for their movement.

“Focal adhesions are where cells attach to the matrix that surrounds them,” Neish says. “The cells lay them down on one side and remove them on the other side, like the tracks of a bulldozer.”

In studying the effect of Lactobacillus rhamnosus on intestines in mice, Neish’s team focused on the small intestine, which normally has fewer bacteria than the colon. This allowed them to avoid using antibiotics to remove naturally existing bacteria beforehand, and to see ROS production in tissue from live animals.

Antioxidants that mop up ROS prevent the bacteria from promoting wound healing in the laboratory, the researchers showed. Neish says his team’s finding suggests that large amounts of antioxidants by humans could interfere with the ability of bacteria to promote intestinal healing.

Previously, it was known that immune cells respond to bacteria by producing ROS, but Neish and his colleagues believe the ROS production they observed stimulates tissue maintenance and is a marker of cohabitation and adaptation, rather than defense.

Oxidative stress, or an imbalance of reactive oxygen species throughout the body, has been linked to diseases such as heart disease and stroke. However, scientists have learned in recent years that cells can also use reactive oxygen species in a controlled, local way to send signals needed for normal functions.

Neish says his team is working to determine which part of the bacteria is responsible for inducing cells to produce ROS. Once identified, this component could be used to encourage intestinal healing in situations where contact with large amounts of live bacteria might be dangerous, such as in premature babies or critically ill adults.

The research was supported by the National Institutes of Health.

Writer: Quinn Eastman

Reference:

P.A. Swanson II et al. Enteric commensal bacteria potentiate epithelial restitution via reactive oxygen species-mediated inactivation of focal adhesion kinase phosphatases. PNAS Early Edition (2011).

The Robert W. Woodruff Health Sciences Center of Emory University is an academic health science and service center focused on missions of teaching, research, health care and public service.

Learn more about Emory’s health sciences:
Blog: http://emoryhealthblog.com
Twitter: @emoryhealthsci
Web: http://emoryhealthsciences.org

Kerry Ludlam | EurekAlert!
Further information:
http://www.emory.edu

More articles from Life Sciences:

nachricht Toward a 'smart' patch that automatically delivers insulin when needed
18.01.2017 | American Chemical Society

nachricht 127 at one blow...
18.01.2017 | Stiftung Zoologisches Forschungsmuseum Alexander Koenig, Leibniz-Institut für Biodiversität der Tiere

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>