Gut Microbiome in Health & Disease (University of Alberta, October 21, 2024) PDF

THE ROLE OF GUT MICROBIOME IN HEALTH AND DISEASE October 21, 2024 Today’s objectives Define key terminology of the microbiome Identify and understand the role of the microbiome in health and disease Consider the effect of antibiotic use, diet, and supplements on the microbiome...

THE ROLE OF GUT MICROBIOME IN HEALTH AND DISEASE October 21, 2024 Today’s objectives Define key terminology of the microbiome Identify and understand the role of the microbiome in health and disease Consider the effect of antibiotic use, diet, and supplements on the microbiome 2  Gut microbiota dysbiosis Abnormal behavioural phenotype Anxiety Fear/Phobia Aggression Cognitive impairment Environmental/Genetic Factors Diet (fibre, protein, fat, processed) Genetics (Serotonin receptors, BDNF, immune modulation) Gut microbial factors Disease (Chronic enteropathy) SCFA/other metabolites Antibiotics Gut microbiota homeostasis Normal behavioural phenotype 3 Some key terminology Microbiome: the population of all microbes in a given area Microbiota: microbes that make up the microbiome Homeostasis: in harmony or balance Dysbiosis: out of balance Symbiosis: a mutually beneficial relationship 4 Symbiosis We live with trillions of microbes in our gut When all is well, these microbes help to breakdown food and provide us with nutrients and metabolites that serve many functions → Regulate immune system, influence metabolism and behavior, and prevent colonization of microbial pathogens 5 The gut microbiome Consists of non-pathogenic bacteria, yeast, and even some protozoa Humans and animals are born with a microbiome…different if surgical birth or antibiotics used early Composition varies due to numerous factors including age, environment, diet, geography! 6  Germfree animal models show the importance of the microbiome! Germfree is not good! Decreased learning ability Increased inflammation and auto-immunity Increased fear, anxiety, depression and aggression 8 Dysbiosis Considered a disease state Caused by early life factors, genetics, diet, environment, other diseases, ANTIBIOTICS Dysbiosis is multifactorial and has many variable outcomes! 9 Prebiotics and probiotics More terminology: -Prebiotics “feed” the gut microbes: usually some type of soluble fibre (Example: psyllium) -Fibre fermentation by microbiome increases short chain fatty acid production which in turn promotes immune system regulation, metabolic regulation, host cell proliferation 10 Prebiotics and probiotics More terminology: -Probiotics: introduces “beneficial” bacteria into the gut. →Lactobacillus sp., Bifidobacterium sp. -There are many probiotic products making great claim, but there is one problem… 11 Do probiotics actually stay and live in the gut? Why probiotics are not magical The microbiome is a complex ecosystem…not just any bacteria can move in and establish due to colonization resistance! -Most do not survive and colonize for longer than 10-21 days -Need to be taken continuously in order to continue finding them in feces…so do they actually work? -The species and subspecies of bacterium that resolves dysbiosis varies between individuals -Some studies show negative effects 13 How do we resolve dysbiosis It is complex! -Time -Diet/environment -Control inflammation and/or autoimmunity 14 Why does microbiome dysbiosis cause so much trouble? Dysregulation/activation of the local immune system → inflammation Can become chronic and systemic, or lead to auto-immunity Direct damage to the enterocytes Chronic enteropathy compounds dysbiosis Allows pathogens to colonize 15 Some outcomes of dysbiosis Grain overload in horses ie; increased starch entering the cecum causes dysbiosis resulting in systemic inflammation → laminitis Cecal dysbiosis in rabbits: often causes death Sudden changes in diet in dogs causes diarrhea due to the microbiome Diarrheal disease in cattle Increased susceptibility to pathogenic bacterial infection Increased behaviuoural issues 16 https://www.nature.com/articles/s41392-022-00974- 4#:~:text=Generally%2C%20the%20gut%20microbiota%20is,Bacteroidetes%20are%20the%20 major%20types.  How does the gut microbiome affect the brain?! You are what your bacteria eat! Metabolite produced by gut microbes contribute to Tryptophan production…a key amino acid that leads to serotonin synthesis https://www.sciencedirect.com/science/article/pii/S21618313 19 Antibiotic effects on the microbiome The microbiome can take months to recover from antibiotic treatment Early life antibiotic use appears to have the most detrimental effects Example: metronidazole use makes way for E.coli to take over Solution: use antibiotics only if indicated by clinical signs and diagnostics -use prebiotics when antibiotics are prescribed -avoid raw food and pea protein based/grain free diets 21 Questions? Announcements Wednesday is an asynchronous lecture so don’t come to class! Friday is guest lecture by Dr. Kassi Boyd (I may not make it to class) Quiz this Thursday Lab topic will be posted later today (no pre-lab participation required)