Viruses Found in the Gut May Help Fight Infections

[Wally]

Natural Gut Viruses Join Bacterial Cousins in Maintaining Health and Fighting Infections
Microbiologists say they have what may be the first strong evidence that the natural presence of viruses in the gut — or what they call the ‘virome’ — plays a health-maintenance and infection-fighting role similar to that of the intestinal bacteria that dwell there and make up the “microbiome.”

Click on link to read this article - http://www.sciencedaily.com/releases/2014/11/141119132454.htm

 

[ahmo]

nfection with the common murine norovirus, or MNV, helped mice repair intestinal tissue damaged by inflammation and helped restore the gut's immune defenses after its microbiome had been wiped out by antibiotic therapy.
In a report on their work to be published in the journal Nature online Nov. 19, researchers say they also found that MNV bolstered the immune system in fighting off tissue damage.

"Our research offers compelling data about the mutually supportive relationship between viruses and bacteria in the mouse gut and lays the groundwork for further research on precisely how the virome supports the immune system, which likely applies to humans, as well," says senior study investigator Ken Cadwell, PhD, an assistant professor at NYU Langone.

 

[adreno]

So indiscriminantly taking antivirals might be as bad as taking antibiotics?

 

[Bob]

There's also a New York Times article.

So, this research could potentially have implications for people with IBS.

The title of the science articles are unhelpful: There are conflicting findings, depending on the genes of the mice. The importance of the findings are based upon the idea that the virus can be beneficial or harmful, depending on the genes of the infected individual. And this may have implications for people with inflammatory bowel disease.

I struggled to follow the logic of the articles, but my understanding so far is that...



Germ Free Mice

Germ-free mice fail to develop a mature gut, including failing to produce adequate villi, and failing to mount a proper gut immune response.

"Germ-free mice also fail to develop a normal supply of the immune cells nestled in the lining of the gut, which attack pathogens but not harmless microbes. As a result, the germ-free mouse’s gut becomes vulnerable to injuries and infections."

However, when germ-free mice were administered murine norovirus (which is harmless in healthy mice - and is related to the human strain that causes vomiting and diarrhoea) "the animals developed intestines and an immune system that were fairly normal."


Mice bred with mutation

Now, we switch the discussion from germ-free mice, to mice bred with a genetic mutation which is known to increase the risk of inflammatory bowel disease in humans. When these mutated mice are exposed to murine norovirus (harmless in healthy mice), they develop gut inflammation or "inflammatory bowel disease."


Normal Adult Mice

When normal adult mice were administered with antibiotics, the guts returned to normal when the antibiotics were followed by administering the murine norovirus. Also, normal mice that were exposed to gut damage, survived longer if they were pre-exposed to the murine norovirus.


Humans

When taking antibiotics, our villi are damaged.

"Heavy doses of antibiotics, which kill off much of the microbiome, can lead to drastic changes in the gut. Some villi die, and the population of immune cells drops. But as bacteria return to the gut, the damage gets fixed."


My Conclusion

So, if I've understood it correctly, normal and germ-free mice benefit from infection with the virus, but mice genetically predisposed to inflammatory bowel disorder (because of a genetic mutation) developed inflammatory bowel disease.

"When [the researchers] prevented germ-free mice from making a [specific] receptor on the surface of their cells, infection with norovirus didn’t lead to an improvement in their guts. That receptor only latches onto one type of molecule. It’s called Type 1 interferon, and it’s produced by cells when they’re invaded by viruses."

So perhaps there's a therapeutic clue there, for people with IBD?

Sounds like it could have interesting potential implications for people with IBS.

 

[JAM]

So indiscriminantly taking antivirals might be as bad as taking antibiotics?

The plant based anti-biotics don't seem to wipe everything out. Hopefully the same will be true of the antivirals. If anything, my IBS symptoms have gotten much better since I started taking OLE.

 

[alex3619]

Bacteriophages are part of the natural ecology in the gut. We simply do not know enough about them to make informed decisions. Bacteriophage therapy has languished for decades, but its a promising option for treating bacterial infections.

At one point I asked if we might have a bacteriophage infection driving ME. Its never been adequately answered. Lipkin might eventually do that.

The right bacteriophage may also alter your gut microbiome - do it right and it could help.

Antivirals tend to be highly specific. Only some bacteriophages, if any, are likely to be affected.

 

[Bob]

Going back to my earlier post, the article headlines that viruses are beneficial for the gut seems to be incorrect for the mice that have IBS...
If I've interpreted the articles correctly, the opposite is true for the mice with IBS - the virus was harmful for them, and precipitated IBS.
So, it seems to me that people with IBS might potentially benefit from antivirals that treat the human version norovirus, if the mouse model can be translated to humans.