Special viruses protect the intestinal health

Study on mice: Like certain bacteria, viruses could have a protective effect on the intestinal flora

20/11/2014

Bacteria have a significant impact on gut health. That viruses could play an important role in the gut flora, but was long doubted. Scientists at the University of New York have recently shown in a study with mice that viruses have a similar protective effect as symbiotic bacteria. The microbiologists published their findings in the journal „Nature“. So far, viral infections were considered more harmful to the gut.

Viruses had a positive effect on attacked intestinal flora
The intestine of mammals is colonized by countless microorganisms that are classified as beneficial to health. Thus, some bacteria help in the defense against pathogens or protect against inflammation. In contrast, viral infections in the intestine were considered harmful for a long time. However, Elisabeth Kernbauer and her colleagues were able to show that noroviruses (murine norovirus) have a positive effect on the intestinal flora in mice. Thus, viruses could perform as important a health function as symbiotic intestinal bacteria.

In their study, Kernbauer and her colleagues infected mice with mouse norovirus. Noroviruses cause unpleasant gastrointestinal inflammation in humans. The mice were two types of experimental animals: one had an intestinal flora attacked by antibiotics and the others were microbiologically sterile by a special breed, so they lacked protective bacteria in the gut.

As the investigations revealed, norovirus treatment had a positive effect on both mouse species. Thus, the intestinal villi were strengthened and the number of B and T cells increased, which play an important role in the immune system.

In addition to symbiotic bacteria, it is very likely that beneficial viruses are also found in the human gut
To check how effective this one is „viral protection“ The researchers gave the mice a chemical that harms the gut. Again, norovirus infection had a positive effect in that the viruses increased the survival chances of the animals. According to the study protect the Noroviruses at least in mice from harmful microbes and chemically induced intestinal damage.

„These data show that eukaryotic viruses have the ability to support intestinal homeostasis and to build mucosal immunity, similar to symbiotic bacteria“, the researchers write in the journal. It therefore suggests that useful symbiotic viruses occur in the intestinal tract of mammals.

Viruses could help patients with intestinal inflammation
Commenting on the study, the two microbiologists Yao Wang and Julie Pfeiffer of the University of Texas at Dallas point out that "some viruses are already known to have a positive effect." These include "herpesviruses that counteract bacterial infections". „This work is now the first evidence of beneficial effects of mammalian intestinal viruses, "the agency quoted „dpa“ the scientists. It must now be clarified in the context of further studies, whether the viruses also support a healthy intestinal flora. In addition, it is still unclear whether they are permanently or only temporarily present in the intestinal tract.

Perhaps the intestinal viruses could also be used probiotically, so the microbiologists. In some cases, patients with intestinal inflammation can help with a chair transplantation of a healthy donor. „Perhaps some of the positive effects of such a transplantation are due to the viruses that were in the donor sample, "speculate Wang and Pfeiffer.