Definitions

BIOLOGICAL BARRIERS

Surface delimiting the organs, playing the double role of protection and exchanges with the environment. In this project, epithelial cutaneous (skin), intestinal epithelial (intestine), pulmonary epithelial (lung), haematoencephalic (brain) and endothelium (blood vessel) barriers are studied.

For all chronic inflammatory pathologies, barriers lose their functionalities by being porous (they allow the passage of a larger number of molecules including pathogenic toxins or microorganisms) and concentrate a greater number of molecules of stress and inflammation.

Microbiota

It is the set of microorganisms (bacteria, yeasts, viruses) present in our body. Only bacteria will be studied in this project. They are necessary for our survival and play a major role in our development and the establishment of all our organs.
Each organ is colonized by a microbiota of its own. The most important is the intestinal microbiota consisting of nearly 5kg of microorganisms. Each microbiote is defined by a richness (number of bacteria) and diversity (number of species) that evolve over the life cycle with relative stability in adulthood. However, the microbiota may evolve more or less rapidly depending on its environment, diet, pre/probiotic or antibiotic intake.

It has been shown that the microbiota of healthy people differs from that of sick people. This is also true for chronic inflammatory diseases: some bacteria produce anti-inflammatory molecules while others are pro-inflammatory. Inflammation is triggered when the balance between these molecules is disrupted by external events.

Systemic disease

A disease characterized by inflammatory and immunological damage to connective tissue and by the spread of lesions whose origin is mostly unknown.

Illness/chronic disease

Chronic diseases are long-term conditions that generally progress slowly.

Molecular biomarker

A measurable physiological or biological (at the molecular level) parameter that allows the in vivo evolution of a disease or process to be monitored.

Predictive biomarker

A physiological or biological parameter that predicts the response to a treatment or the evolution of a pathology

Affitin

A small protein that binds to a target molecule.

Metabolite

A molecule resulting from the biochemical transformation of an initial molecule by the metabolism of an organism.

Extracellular vesicle

Vesicles from cells or bacteria that are released into the external environment either by exocytosis (exosomes) or by budding of the extracellular membrane (microparticles). These vesicles contain proteins, lipids, DNA molecules and RNA molecules from their initial excretory cells.