“We need to collect the stools of 100,000 people for microbiota mapping”

“Show me your microbiota, I’ll tell you if you’re healthy. And if you will remain so. Now called the second brain, our intestinal microbiota is a true reflection of our general state of health. Composed of billions of bacteria, however, it has not revealed its many secrets. And this is what Le French Gut, a research project led by INRAE ​​and carried out in collaboration with AP-HP, will try to pierce.

The objective: “Mapping the intestinal microbiota in France to better define its composition, explains to 20 minutes Joël Doré, research director specializing in microbiota at INRAE ​​and scientific coordinator of French Gut. And analyze the link between its variations and the development of certain diseases”. But to achieve this, scientists need matter. They are thus launching an appeal for donations aimed at collecting “a stool sample and the nutritional and clinical data of 100,000 volunteers over the next five years”, continues Joël Doré, who has been studying the microbiota for more than forty years. He responds to 20 minutes.

Why does the French Gut need stool samples from 100,000 individuals? Why so much?

Knowledge of the microbiota has progressed enormously over the past twenty years. And today, in the same way that we learned to sequence the human genome, we are undertaking the sequencing of all the genes and microorganisms that make up our intestinal microbiota. We are microbial beings, with a microbiota in our intestines, lungs, urogenital sphere or skin. We are in constant interaction with 50,000 billion bacteria and microbes.

And the intestinal microbiota is in dialogue with our entire body. However, we still have a lot to discover about it, or rather about them: we have been able to observe that in the general population in good health, there is a rather incredible heterogeneity of the intestinal microbiota, with almost as many unique microbiotas as individuals. . This building knowledge needs to be backed up by a very broad baseline.

The French Gut is a unique project, open to individuals in good health, but also in collaboration with doctors to integrate cohorts of patients with chronic diseases, in order to have a representative panel. This involves studying the role of food, pollution and a set of factors on the microbiota.

This project aims in particular to model and predict changes in the intestinal microbiota associated with diseases. Does this mean that having a weak or unbalanced microbiota paves the way for the development of certain pathologies?

Absolutely ! The incidence rate of pathologies in our modern societies has exploded for three generations, without our having any control. However, the microbiota plays a very important role: if it is healthy, it can constitute a protective shield against a range of diseases. But if it is weak or in dysbiosis, it can cause intestinal permeability, which will generate inflammation, oxidative stress and lower immunity.

A vicious circle then begins which makes the microbiota a factor favoring the development of many chronic diseases: IBD (inflammatory bowel disease), metabolic diseases such as diabetes or obesity, but also certain cancers and many of neurological diseases.

One of the axes of the French Gut will thus focus on the study of the link between intestinal microbiota and chronic diseases, but also neuro-developmental disorders such as autism, schizophrenia and bipolarity, or with neurodegenerative diseases such as Parkinson’s. .

By carrying out this mapping of the microbiota, can we hope to make it a health prevention tool? Even a drug?

This project aims to develop diagnosis and therapeutic optimization: the microbiota can be a predictive tool. In the treatment of cancer, it has been demonstrated that certain weak or unbalanced microbiota are predictive of the non-response to immunotherapy. In the field of obesity, patients with a particularly depleted microbiota will generally fail to regulate their weight, improve their inflammation or reduce their symptoms of diabetes.

This therefore means that there is a component of therapeutic innovation to be developed: we will be able to use the microbiota either as a lever or as a kind of medicine. We think we can go as far as the process of transferring microbiota from a healthy individual to a sick individual to transform a patient who does not respond to a treatment into a responder.

We can therefore think that in the face of certain diseases, taking into account the component of the intestinal microbiota could lead to more efficiency and performance in therapeutic approaches. It’s hypothetical, even if there are already a few areas in which this is progressing. This is already a reality in the field of the fight against IBD, such as Crohn’s disease or ulcerative colitis, where the transfer of faecal microbiota from a healthy individual allows the transplanted patient to rebuild an intestinal microbiota by symbiosis. It acts like a drug, with a great improvement in the symptoms of the disease.

How can we act on the quality of our microbiota? And how can everyone make their “contribution” to science?

The French Gut aims to move towards personalized preventive nutrition, to provide recommendations to ensure or restore a microbiota whose composition, richness and diversity make it more favorable to the maintenance of good health, to make a chronic disease prevention mechanism. Because everything is linked: microbiota and immune system are mirrors that constantly interact.

Everyone can contribute by answering our call for donations. It’s quite taboo to ask people to self-collect a stool sample. But the general public’s interest in the microbiota has created a craze. And it’s very simple, you just have to be of legal age and go to our LeFrenchGut site, check your eligibility (not having taken a ‘antibiotics recently) and complete a fifteen-minute questionnaire, before receiving a self-collection kit to be returned by post in a stabilization liquid. The sample will be subjected to sequencing, and will join our reference base.

The French Gut is part of an international project, the “Million microbiomes of humans”, which aims to map one million human microbiota and build the largest database in the world.

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