Tiny Helpers - Billions of phages colonize human bodies

Bacteria-specific viruses leave the gut and migrate to all regions of the body

There are innumerable bacteria-specific viruses in the human body, which are also called phages. These phages can easily migrate from the intestine into the blood and other organs. Researchers now found that about 30 billion phages from the gut migrate into our bodies each day, probably providing useful health services.

San Diego State University researchers found that so-called phages are able to cross the cells of epithelial layers. This allows them to get out of our intestines into human tissues and develop beneficial effects on our health. The experts published the results of their study in the journal "mBio".

The growing knowledge about viruses and bacteria allows a better understanding of their effects on humans. (Image: bluedesign / fotolia.com)

Phages are useful organisms

On and in the human body teeming with tiny organisms. These live, for example, in our intestines, in our noses and on our skin. Often, these organisms are useful and support human health. Examples of these subtenants are bacteria, amoebae and fungi. But also billions of phages belong to the useful organisms, the medical scientists report from their current research results. Such phages are specialized in bacteria.

Researchers clarify important questions about phages

Phages are among the most numerous organisms on our planet, say the experts. Actually, phages are almost everywhere. They are found in the waters of the oceans, in the ground, on and in the human body. In the human body, for example, the phages are found in the blood, in the human lymphatic fluid and in various other organs, explain the scientists. So far, however, it was still unclear how the so-called phages got there. It was also unknown how many phages are found on a human. The scientists at San Diego State University have now tried to clarify this ambiguity in their study. The experts were able to determine that phages are particularly common in mucus layers to protect our intestinal wall. The physicians wondered if the phages could migrate through this mucus and penetrate from the gut to other areas of the body.

Each virus can traverse the epithelial layer in a few minutes

For verification, the researchers performed a series of experiments with human epithelial cells. These epithelial cells form a protective layer around all internal and external body surfaces. For example, they also cover the intestines and lungs of humans. The scientists found that the cells of these boundary layers continuously absorb phages. So the phages are then transported to the other side. However, it is still unclear how exactly this transport mechanism works, explains researcher Sophie Nguyen from San Diego State University. However, in their current study, the scientists were able to prove that every virus can cross the epithelial layer within just a few minutes.

30 billion phages migrate from the intestine into the body every day

The research shows that an estimated 30 billion phages per day migrate from the gut of an average person into the body, the researchers report. There they are distributed in the blood, the lymph and in various other organs.

Effects of viruses on human health?

The previous assumption that phages do not interact with eukaryotic cells seems to have turned out to be false, co-author Jeremy Barr. The viruses appear to be useful to our body, for example to positively affect the human immune system. Other studies also point to such relationships. However, it will take some time for the medical profession to fully understand the exact impact of these viruses on human health. (As)