Flying can affect your stomach

Bacteria in the gut affect aging

The bacteria in our intestines play an important role in our health. The microbes not only help with digestion, but also affect the immune system. Conversely, problems with the immune system can throw the bacterial community in the intestine out of balance. This imbalance can cause age-related diseases.

How exactly this is related has now been investigated by scientists from the EPFL in Lausanne using fruit flies. The scientists working with Igor Iatsenko and Bruno Lemaitre have removed a receptor in the flies' immune system called PGRP-SD, which allows them to recognize pathogenic bacteria and attack them with immune cells. Without this receptor, the flies would not have a functioning immune system.

On the one hand, the animals had a shorter lifespan, and on the other hand, the researchers found that the distribution of forces in the bacterial community in their intestines had shifted: they came across the bacterium Lactobacillus plantarum, a common lactic acid bacterium.

Damage to cells

As Iatsenko and colleagues report in the journal "Immunity", the bacteria produced an excess of lactic acid, which in turn led to the formation of highly reactive oxygen radicals. These cause damage to cells and thus contribute to the aging of the tissue.

Conversely, when the scientists increased the amount of the immune receptor PGRP-SD in fruit flies, the intestinal flora remained in balance and the life span of the animals was even longer, according to EPFL. The scientists suspect that similar processes also take place in the intestines of mammals.

"Our study identifies a specific member of the bacterial community and its metabolic product that influences tissue aging in the host organism," says Iatsenko. There are definitely more such examples, and a better understanding of the interactions between host and bacterial community and their influence on aging is necessary in order to develop strategies against age-related diseases. (APA, November 14, 2018)