Gut-Brain Axis

Question 1

Neuropsychiatric disorders include

Answer 1

mood thinking or behavioral disorders

Question 2

Disorder vs disease

Answer 2

disorder - no lab test
disease - is a test

Question 3

Clear examples of altered brain function by infections

Answer 3

Question 4

The gut-brain axis

Answer 4

a bidirectional link between
the CNS and the gastrointestinal track, mediated by
endocrine,
immune,
and neural signaling

Question 5

microbiota

Answer 5

all the microorganisms living in stable association with their host (i.e. the intestines)

• 10 times more than human cells - misconception actually 2 – 3 times more in a healthy individual - depends on nutritional status of person - hygiene hypothesis

Disruptions to composition associated with allergies and metabolic disorders

Question 6

hygiene hypothesis

Answer 6

too clean - not being exposed to things anymore

Question 7

microbiome

Answer 7

genetic content (DNA) - sequenced – can see everything present (inc. viruses, parasites, fungi)

many thing in gut cannot grow in-vitro

Question 8

Gut – immune link

Answer 8

acquisition of microbiota during birth essential to train immune tolerance - microbial signature of baby

(twins - can predict disease development based on early changes in microbiota)

Question 9

The vagus nerve

Answer 9

the 10th cranial nerve; longest nerve in the autonomic nervous system (PNS), connecting the GI tract to the brain stem

Question 10

Bacterial mediators

Answer 10

produce precursors to (ex. tryptophan - GABA), or actual, neurotransmitters (serotonin)

Question 11

The hypothalamic-pituitary-adrenal (HPA) circuit

Answer 11

the brain’s stress response system

response to external stress (ex. hunger)

response has efect on microbiota

Question 12

Bacterial metabolites act upon all the different interfaces in the gut:

Answer 12

the epithelial
the immune
the neural

Question 13

pathology of gut brain axis

Answer 13

Question 14

pathology of gut brain axis before and after response from brain

Answer 14

Question 15

Gut brain axis balanced state

Answer 15

Balance of pro- and anti-inflammatory cytokines

Balanced state: the epithelial and immune cells are “trained” in tolerance to “correct” microbiota AND microbiota is “adapted” to host’s biochemical “normal” response

Question 16

Gut brain axis unbalanced state

Answer 16

Unbalanced state: small change in either microbiota composition or host’s biochemical response can lead to uncontrolled dysregulation (butterfly effect), leading to pathology

Question 17

Gut brain axis in disease

Answer 17

autoimmune diseases
autism
depression and anxiety
obesity

Question 18

Gut brain axis in autoimmune dieseases

Answer 18

hygiene hypothesis - destroy period of immune training (farm animals - antibiotics, hormones; homes - so clean)

Immune system training disrupted

Aberrant immune reactions (asthma, allergies, MS) [b/c immune response b/c changes in biota]

Question 19

Gut brain axis in autism

Answer 19

Correlation between autism and dysbiosis of the gut

Picky eating habits, genetics, or environmental factors, not clear (controversial - cause vs consequence)

Question 20

Gut brain axis in depression and anxiety

Answer 20

High correlation between intestinal disorders and mental illness

can use antidepressants to treat IBS - brain response - effect on body

Question 21

Gut brain axis in obesity

Answer 21

Correlation between gut microbiota and misregulation in the CNS control of food intake

altered micobiota - blocks CNS response that makes feel full

Question 22

ex. bactera change and brain disturbances

Answer 22

Question 23

Ways the gut brain axis can affect health/disease

Answer 23

1. Gut microbiota dysbiosis (many things can cause, hunger, fear etc.)
2. Inflammation (infection can cause)→ leaky gut
3. Leaky gut → (antigen from gram neg bacteria) LPS exposure → inflammation
4. Chronic stress → High cortisol levels
5. High cortisol → go back to (1) and (2)

Question 24

Gut brain axis what causes what

Answer 24

Question 25

PD and gut-brain axis

Answer 25

GI infection - protect by producing alfa -syn - can be prion like - go from gut to brain alfa-syn found many places outside the brain

Question 26

AD and gut-brain axis

Answer 26

brain microbiome project - sequence everything in brain - AD all sours of viruses etc. healthy brains not have short term: infect - die - accumulation of placks - infect and not die - may be beneficial

Question 27

Any protein with ability to aggregate and grow plaques can (in theory) be

Answer 27

antimicrobial However, if over generated or for a long time still results in pathology - a type of dysregulated innate immune response

Question 28

how aggregates can be protective / antimicrobial

Answer 28

Question 29

the third brain

Answer 29

Question 30

where is third brain coming from

Answer 30

Question 31

___ highlights the connection between mental health and physical health!

Answer 31

MNS umbrella NTs - fuel for brain - microbes in gut produce same brain fuel - connection - cause vs consequence question