6533b862fe1ef96bd12c5f5a

RESEARCH PRODUCT

Impact of polyphenols and feeding rhythms on the immunomodulation properties of the probiotic bacteria in the gastro-intestinal tract

subject

description

The human intestinal microbiota is composed of several types of microorganisms, including bacteria, archaea, fungi, unicellular eukaryotes and viruses. Among them, bacteria are the most diverse and abundant with a gene catalog 150 times larger than the genes present in the human genome, which represents a tremendous metabolic potential. These bacteria actively participate in the maintenance of intestinal homeostasis. Dysbiosis of the gut microbiota could be observed at course of many human pathologies, particularly inflammatory diseases intestinal chronic diseases (IBD), such as Crohn's disease (CD) or Ulcerative colitis (UC). These dysbiosis could contribute to the onset and progression of diseases. For example, gut microbiota transplantation experiments in murine model have allowed to show that a dysbiotic microbiota is sufficient to induce chronic inflammation in the colon and thus lead to the development of a metabolic syndrome or colitis. Different intervention strategies, including fecal transplantation, administration of probiotics or even special nutritional diets have been developed to act on the microbial communities of the digestive tract and to restore homeostasis of host tissues. The success of some interventions like Fecal transplantation represent a proof of concept in humans that acting on the composition of the intestinal microbiota is a strong lever to resolve certain physio pathological situations associated with gut microbiota dysbiosis. Diet is another important method for modulating the gut microbiota since it is the most important factor influencing its composition. In fact, the nutrients ingested can act directly on the composition of the microbiota by serving as substrates for microorganisms and indirectly by modulating intestinal homeostasis and components of the immune system associated, themselves contributing to regulate the composition microbiota. It is expected that ingestion of these beneficial microorga nisms can stimulate the immune system, promote intestinal homeostasis and to some extent contribute to the balance of the microbiota intestinal. The use of probiotic microorganisms is found to be very effective in some studies to treat different physiopathological situations (colitis, metabolic syndrome) in laboratory model organisms (rats, mice), however the use of these same probiotics in humans have given relatively disappointing clinical results, with poorly reproducible results across cohorts of patients. Except for the treatment of antibiotic-associated diarrhea. These discrepancies in results between pre-clinical models and clinical trials encourage better characterization of the molecular mechanisms used by probiotics to exert their beneficial effects and especially better understand the relationship of these probiotic microorganisms with the resident microbiota and diet.Among the different rising intervention strategies practiced nowadays in the purpose to shape the microbiota, a growing interest is given to other dietary interventions, like caloric restriction (CR) which has demonstrated several beneficial effects on various physiological systems, including the gastro-intestinal system, by modulating the innate and adaptative immune responses. In fact, emerging evidence suggests that the immune system function might be heavily influenced by the sensing of nutrient, reinforcing the idea that diet can deeply influence the inflammatory responses.