This document outlines the microbiota-gut-brain axis and its influence on mental health conditions like anxiety and depression. It discusses how gut microbes communicate with the brain through pathways like the vagus nerve, immune system, and neurotransmitters. Certain microbes can produce neurotransmitters like GABA and serotonin that impact brain functions related to mood. Imbalances in the gut microbiome through factors like stress, antibiotics, and diet have been linked to mental health issues by disrupting this axis. Future research aims to better understand these relationships and develop microbiome-targeted treatments and preventions.
3. OUTLINE
⢠Introduction
⢠Gut Microbiota
⢠Microbiota Gut Brain Axis
⢠Communication pathways & Neurobiological Mechanism
⢠Neurotransmitter & Neuropeptide
⢠Influence of Microbioata GBA on Anxiety & Depression
⢠Gut Microbioata Treatment
⢠Conclusion & Future Direction
4. INTRODUCTION
⢠GI------100 trillion MO
ďśLike bacteria, yeast, archea etc.
⢠Imp in development & functioning
ďśLike digestion, growth etc.
⢠Role in diseases
ďśObesity, asthma, diabetes type 2
⢠Recent studies ----- GBA ---- CNS ----- Neuropsychiatric Disorder
ďśMechanism ----- not well understood
ďśResearch ----- bidirectional communication
ďb/w GMB & CNS
ďAnxiety & depression
5. THE GUT MICROBIOTA
⢠Estimated -----10^14 MO
ďś<10 times somatic/ germ cells
⢠3:1 MO to human cell
⢠1/3rd GMB common
⢠2/3rd individual specific ---- personal identity
⢠Microbes ---- host metabolic pathways
ďśFat distribution,
ďśNutrition absorption
⢠Host microbes ---- symbiosis
⢠Dysbiosis ----- mental health
6. Microbiota Gut Brain Axis
⢠Reciprocal Communication
⢠Overlapping pathways :-
ďśNeuroendocrine System
ďśImmune System
ďśAutonomic System
ďśEnteric Nervous System
⢠2 way information exchange
⢠GI-----500 million nerve endings & immune cells
⢠Neuronal & biochemical processes-----GBA
⢠Dysfunction of GBA
ďśEating disorder
ďśStress
ďśInflammation
8. CONTINUEâŚ
FATTY ACIDS
⢠Brain is enriched
⢠Help on regulation
ďśNeurotransmission
ďśCell survival
ďśNeuroinflammation
⢠Production of Eicosanoid----Immune & Inflammatory response
⢠Regulate gene transcription
⢠Microbial derived SCFA---- anti inflammatory properties
⢠Primary metabolite of GB
⢠Spp. Eubacterium, Bifidobacterium, Enterobacter & Lactobacillus
9. CONTINUEâŚ
⢠Produces acetate, butyrate, isobutyrtate, isopropionate
⢠N-butyrate & propionate------neuroactive properties
⢠Role in Enteroendocrine
TRYPTOPHAN
⢠Synthesis of serotonin---depression----gut
⢠Tryptophan & Tryptophan Hydroxylase
⢠Co-influence of tryptophan & immune system
⢠CNS function & Mood disorder
⢠Tryptophan metabolism---- Desregulation ---- Brain & GI disorders
10. NEUROTRANSMITER &
NEUROPEPTIDE
⢠Produced by bacteria
ďśLactobacillus
ďśBifidobacterium
ďśEscherichia
ďśEnterococcus etc.
Neurotransmitter
chemical messenger--- transmit signal---synapse
Neuropeptide
protein--- released in brain---activate receptors--- neuron to communicate
⢠Neuronal signaling messenger
⢠Imbalances effect Brain & Behavior
11.
12. CONTINUEâŚ
GABA
⢠Inhibitory neurotransmitter
⢠Produced by Glutamate metabolism
⢠Dysfunction----Chronic Disease
ďśAnxiety
ďśDepression
⢠Bifidobacterium & Lactobacillus----produces GABA from Glutamate
⢠L.rhamnosus---modulate expression of GABA in CNS
⢠Treatment of depression & anxiety
⢠Vagus Nerve-----necessary
⢠Behavioral & Molecular changes
13. CONTINUEâŚ
SEROTONIN
⢠Monoamine Neurotransmitter
⢠Regulate all brain functions
⢠Modulate physiological processes
ďśMood
ďśSleep
ďśPain
ďśAggression,
⢠Dysregulation-----Neuropsychiatric Disorders
ďśAnxiety & Depression
⢠90% produced-----enterochromaffin cell in GI
⢠Spp. Of Escherichia & Enterococcus
ďśDirectly influence CNS function
14. CONTINUEâŚ
BDNF
⢠Neurotrophin-----CNS
ďśSurvival of existing neuron
ďśEncourages growth
ďśDifferentiation of Neurons & Synapses
⢠Decreased level----chronic depression
⢠mRNA & protein level associated with GBA
⢠Intestinal microbioata-----increases BDNF
⢠In mice infected with
ďśTruchuris muris-----decreased level of BDNF
ďśB. longum-----BDNF level normalized
15. INFLUENCE OF MICROBIOATA GBA ON
ANXIETY & DEPRESSION
Anxiety
ââ Psychological state characterized by apprehension or fear. ââ
Depression
ââMedical illness that negatively affects how you feel, the way you think and how you act.ââ
ďśMore than 350 million suffer
ďśContribute to
ďLoss of productivity
ďIncrease Annual health care cost
ďEconomic burden to public health care system
⢠Etiology of disorders unknown
16. CONTINUEâŚ
⢠Proposed Neurobiological Mechanisms
ďśChemical imbalance
ďśIllness
ďśInflammation
ďśReduction in Neurotransmitters
ďśChange in Neuroendocrinal Pathways & Hormones
ďśStress
ďAutonomic Nervous System (ANS)
ďComplex interaction with metabolism
ďPro- & Anti-inflammatory components of immune system
⢠Gut MB role in treatment & prevention
17. CONTINUEâŚ
Microbes & Stress
ďśResearch from Neurobiology & Microbiology
ďNatural barrier defenses----- disturbed by exposure to biological stressors
ďEg study by Tannock & Savage 1974
ďMoving mice----- cage
ďLacking bedding, food, water---reduced number of Lactobacilli
ďPotential cause----novel housing
Influence of Psychological stressor on Microbial Health
ďInfant rhesus monkey-----mother separation(stressor)
ďLowered cultured Lactobacilli
Microbiome of organism exposed to stressor differed from non stressed organism
18. GUT MICROBIOATA TREATMENT
⢠Probiotics
ââLiving MO that believed to provide health benefits when consumed.ââ
ďśLactobacillus & Bifidobacterium
ďśAlter composition & diversity of GMB
⢠Antibiotics
ďśAntibacterials
ďśUsed in treatment & prevention of bacteria
ďśEffect microbiota GBA
ďśEg mice---antibiotics---7 days
ďśReduced anxiety like & increase exploratory behavior
⢠Transplant
ďśFMT---effective
19. CONCLUSION & FUTURE DIRECTION
⢠Early stage of understanding
⢠Microbe play imp role in
ďśImmune function
ďśStress responding
ďśBrain function and behavior
⢠Stress affect composition of GMB
⢠Various treatment alter GMB---behavior & health outcome
⢠These studies----innovative approach---prevention & treatment of disorders
⢠Future work---elucidate---interceptive connection
⢠Advancement in brain based disorders