Microbiota.pdf

Microbiota and health Pr. Roberta FORESTI Professor of Biochemistry, Faculty of Health, UPEC [email protected]  What is the gut microbiota? The microbiota is the collection of microorganisms in a person's gastrointestinal tract. This includes many bacteria, fung...

Microbiota and health Pr. Roberta FORESTI Professor of Biochemistry, Faculty of Health, UPEC [email protected]  What is the gut microbiota? The microbiota is the collection of microorganisms in a person's gastrointestinal tract. This includes many bacteria, fungi and viruses. The gut microbiota has co-evolved and exists symbiotically within the human digestive system. We are the ‘host’ of the microbiota Gut microbiota Willem M de Vos et al. Gut 2022;71:1020-1032 How many microbes are in our body? It is estimated that 100 trillion microbes live in our gut (100 followed by 12 zero!) representing as many as 5,000 different species and weighing approximately 2 kilograms. Note that we have more microbes than cells (36 trillion in adult male humans), Why do we need the microbiota in our gut? Most food is broken down in the gastrointestinal tract by human enzymes. However, dietary fibers are carbohydrates that can only be digested by the gut microbiota. What does the gut microbiota do? Brain SCFAs Short Chain Fatty Acids Beneficial effects on host metabolism, Lung immune system and function of different organs Liver Bones  Production of beneficial or toxic metabolites by the microbiota LPS Fatty acids metabolism MAMPs Cholesterol metabolism Toxins Tryptophan Secondary bile acids Indoles Primary bile acids Amino acids Bile acids degradation metabolism Regulation of metabolism Gut microbiota Gut integrity/inflammation Fermentation Carbohydrates Anti-inflammatory SCFAs Anti-diabetic Anti-obesity TMAO, a toxin produced by bad gut bacteria How do we define a healthy microbiota? Normal Firm Abnormal Firm >> 1 > 1 Normal Abnormal composition composition Rinanda T. et al. Gut Pathogens 15, 54 (2023) Proof that microbiota contributes to undernutrition in children Mice receiving microbiota from children Body weight (%) Healthy Stunted (Undernourished) Fecal Fecal microbiota microbiota Lean mass (%) Transplantation (Colonization) Blanton LV et al. Science 351, 6275, 2016 Therapeutic interventions for a healthier microbiota Diets Prebiotics Probiotics Postbiotics Faecal microbiota transplantation Therapeutic interventions for a healthier microbiota Prebiotics = non-digestible food ingredients that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves host health (examples: oligosaccharides and dietary fibres found in garlic, leeks, onions, oats and many fruits and vegetables) Postbiotics = metabolites secreted by live bacteria that provide benefits to the host (examples: fermented foods contain postbiotics: yogurt, kimchi, kefir, sourdough bread) Probiotics = live microorganisms that can provide health benefits when consumed, usually by improving the gut microbiota (examples: Lactobacilli acidophilus, Bifidobacterium, Akkermansia muciniphila) Sources and functions of prebiotics Bifidiobacterium Enterococcus faecalis Compylobacter Clostridium Lactobacillus difficile Escherichia coli Negative correlation between obesity and Akkermansia muciniphila 35 30 *# Akkermansia muciniphila (relative gene expression) 25 Obese (OO) Control (C) Akkermansia 20 muciniphila 15 A Gram-negative 10 anaerobic bacterium that produces SCFAs 5 in the human gut ** 0 S S D F D n -C O H -M D FD HF H SD = Standard Diet HFD = High Fat Diet The beneficial effects of the species Akkermansia muciniphila Akkermansia muciniphila as a probiotic in humans Beneficial effects of the new generation of probiotics