New bacterium shows promise for treating type 2 diabetes, obesity

It all started, when Patrice Cani, FNRS researcher at University of Louvain (UCLouvain), and his team repeatedly observed that a bacterium (called Subdoligranulum) is almost absent in obese and diabetic people, while it is systematically present in healthy people. So, they decided to take a closer look at this "family" of bacteria.

There is as yet only one cultivated strain of this family available in the world (the only known member of a large family) and, no luck, it is not the strain that was observed to be decreased in sick people. This is not unusual: nearly 70% of bacteria in the intestine have not yet been identified (this is called the dark matter of the intestine).

In 2015, the team then set out to isolate the bacterium themselves in order to learn about its action on the human body, knowing that it is only present in healthy people. For 2 years, the scientists searched, isolated and cultivated nearly 600 bacteria from the intestine, in an attempt to find a second member of the family. All in vain.

Instead, the UCLouvain team uncovered a bacterium of a new kind, still unknown until then. This achievement is already extraordinary in itself: very few scientists have the opportunity in their careers to discover a new genus of bacteria, and name it. The name they chose?

Dysosmobacter welbionis. Dysosmo ("which smells bad", in Greek), bacter (bacterium) is the bacterium which stinks (!), "Because, when you grow it, it has a slight odor". Welbionis for WELBIO, the organization in the Walloon region which funded this research.

The peculiarity of this bacterium? To begin with, it produces butyrate. Nothing exceptional so far, many other bacteria produce this molecule that is known to decrease the risk of colon cancer, for example by strengthening the intestinal barrier and boost immunity. But the team also observed that Dysosmobacter welbionis was less present in people with type 2 diabetes.

Through the analysis of 12,000 fecal samples (microbiota) from around the world (i.e. a very representative population sample), the UCLouvain scientists observed that the bacteria is present in 70% of the population (which is huge). A surprising discovery. With such a presence, how come it has never been discovered before? Part of the answer probably lies in the improved cultivation techniques developed by the UCLouvain team.

The UCLouvain team including Emilie Moens de Hase (doctoral student) and Tiphaine Le Roy (post-doctoral fellow) then tested the action of Dysosmobacter welbionis in mice. The Results? The bacteria increased the number of mitochondria (a kind of power plants within cells that burns fat), thereby lowering sugar levels and weight, in addition to having strong anti-inflammatory effects.

All these effects are very promising for type 2 diabetic and obese subjects and resemble those of Akkermansia, a beneficial bacterium that is at the heart of the research in Patrice Cani's lab.

Another observation? The bacteria's effects are not limited to the gut: Scientists have found that certain molecules produced by Dysosmobacter migrate around the body and have distant actions as well. This is promising and probably explains the effects of the bacteria on the fat tissues, but also opens the doors for a possible impact on other diseases such as inflammation and cancer. This is currently being investigated by the team.

The next step? To test the action of Dysosmobacter welbionis coupled with that of Akkermansia, in order to see if their association allows to cumulate their effects on health, while always keeping in mind the fight against type 2 diabetes, inflammatory diseases, obesity and cancer.

That's the fun of research: you dig for dinosaur bones and you end up finding a treasure."

Patrice Cani, FNRS Researcher, University of Louvain

The originality of these discoveries? Identifying a new bacterium and giving it a name that will then be used around the world: the number of times this was achieved in Belgium can be counted on the fingers of both hands. But that's not all, the same research team also identified the effects of this bacterium on the body and its potential interest in the fight against certain diseases.