Microbiota 2 Flashcards
2 effects microbiota have on mucous layer?
direct: block binding sites
indirect: interact with pattern recognition receptors on enterocytes
microbiota interact with pattern recognition receptors on enterocytes to do what?
down-regulate
develop tolerance for TLR2, 4
PAMPS from microbiota stim 4 main things on mucous/gut epithelium
stims mucin production
prolif of crypt/Paneth cells
stims antimicrobial peptides
induce regulatory cytokines
SCFAs inhibit what in mucous/gut epithelium?
inflamm cytokines
IL-22 after PAMP interaction does what?
promotes epithelial barrier integrity
When do Peyer’s patches vs. mesenteric lymph nodes develop?
Peyer’s patches : prenatally
mesenteric lymph nodes: post natally
what happens to Peyers patches after vaginal birth?
enlarges
how do you get IgA production in gut?
from B-cells induced by microbiota
do germ free mice have MAIT cells?
nope
lymphocyte subset development’s end goal is to do what?
so it can respond differently to normal microbiota and pathogens
normal microbiota causes what kind of inflamm?
physiological inflamm without damage
pathogens induce what kind of inflamm
damaging pathological inflamm
How does epithelium PRR detect invasion?
TLR5 at basolateral surface
how do epithelium PRR detect friend from foe?
‘senses’ commensals at luminal edge rather than pathogens at the epithelial surface
what does it mean if you have inflammasome signalling and weak TLR binding?
could be a pathogen trying to get in!
what id dysbiosis?
altered normal microbiota
what is involved with kwashiokor?
gut microbiota
what was the Malawian twin kwashiokor study results telling us?
the one with kwashiokor couldn’t recover the gut microbiota even after therapeutic diet
what happened to mice fed kwashiorkor diet?
lost weight, microbiome changed couldn’t recover even most therapeutic diet
why couldn’t the microbiome recover post kwashiorkor? and cause undernutrition?
kwashiorkor microbiota made chemicals that selectively inhibited TCA cycle enzymes affecting energy metabolism
obese people’s microbiome are what?
less diverse
DMII people have what kind of microbiome?
altered, less diverse
less diverse microbiome = ?
higher levels of insulin resistance
serum triglycerides
cholesterol
if you transfer obesity microbiome between animals what happens?
the lean animal become obese!!
lean subjects have more what with obesity associated inflammation?
T-regs
what is increased in inflammation in obese mice?
Bifidobacteria
obesity changes 3 things in gut microbiota
altered composition
altered fermentation
increased energy harvest
inflammatory bowel disease and microflora, describe
elevated immune responses
decreased diversity
increased intestinal permeability
diet, antibiotic and appendectomy does what to microbiota?
reduces diversity
how are microbiota involved with allergies?
seems to be less diversity in infants leads to more allergies
intestinal microbiota and infectious disease are related how? 3 ways
spread of resistance genes
infections at extra-intestinal sites
gut infections
microbiota that escape GIT cause?
UTIs, resp, wound infections
usually need abnormal host
C.Diff can cause what?
pseudomembranous colitis
microbiota if altered could render you more susceptible to what bug?
salmonella or other pathogens
overgrowth of other commensals
C.Diff stats:
gram +ve
anerobic
spore forming
rod
when does C.Diff happen?
overgrows when gut microbiota altered via drugs etc.
what does C.Diff do to you?
adheres to mucosal epithelium, produces toxins
inflamm/bowel necrosis
C.Diff big problem where?
in hospitals: hypervirulent, resistant strains
how to treat C.Diff ?
more antibiotics!
Metronidozole +- vancomycin
who has 4x greater risk of recurrent C.Diff infection?
appendectomy
how do the microbiota of people with recurrent C.diff look?
reduced diversity
hardly any bacteroides
how to treat C. Diff pseudomembranous colitis?
bacteriotherapy i.e.. fecal transplant
success rate of bacteriotherapy?
91-98% success rate
Pre and Probiotics beneficial?
jury’s still out on that one.
may help with recovery from darrhoeas/rotavirus
2 forms of experimental systems to test microbiota interventions?
twins studies
germ free mice
