A15 - Human gut microbiota in Homeostasis II

Which parts of the GI tract can Crohn’s affect?

From the mouth to the anus (Whole GI tract)

Which forms granulomas? Crohn’s or Ulcerative colitis?

Crohn’s disease causes granuloma formation

Which affects all throughout the epithelial layer? Crohn’s or Ulcerative colitis?

Crohn’s disease affects all throughout the layer

Which causes deep fissuring ulcers? Crohn’s or Ulcerative colitis?

Crohn’s causes deep fissuring ulcers

Which can affect the stomach, small intestines, large intestines and rectum? Crohn’s or Ulcerative colitis?

Crohn’s can affect basically the whole GI tract.

Which parts of the GI tract does Ulcerative colitis affect?

The colon only

Which begins in the rectum and spreads proximally? Crohn’s or Ulcerative colitis?

Ulcerative colitis starts in the rectum and spreads proximally

Which mainly only affects the mucosal layer? Crohn’s or Ulcerative colitis?

Ulcerative colitis

Which forms crypt abscesses? Crohn’s or Ulcerative colitis?

Ulcerative colitis forms crypt abscesses

What is the pathogenesis of IBD?

Aberrant inflammatory response to host microbial and/or environmental factors in a genetically pre-disposed individual.

What is the Pre-disease stage of IBD?

Disturbed epithelial bacteria and translocation of microbial products

What is the Acute inflammation stage of IBD?

Activation of immune cells and the induction of an inflammatory response

What is the chronicity or resolution stage of IBD?

The inflammation either

• Resolves itself and IBD does not continue

• Becomes chronic and lasts months/years

What is the Tissue destruction phase of IBD?

Chronic inflammation results in

• Fibrosis

• Abscesses

• Fistulas

• Cancer

What are the four stages of IBD?

Pre-disease stage

Acute inflammation stage

Chronic inflammation stage (or resolution)

Tissue destruction stage

What is a fistula?

An abnormal opening between two parts of the body

• Can also be between a part of the body and the skin

What is the most common treatment for IBD?

Immunosuppression drugs to help prevent inflammation

• This does not fix the dysbiosis which caused the inflammation

What is autophagy?

The recycling of cellular organelles/proteins and degradation of intracellular pathogens

What is produced when pathogenic microorganisms are sensed via TLRs and NLRs?

Differentiation of Th17 and type 3 innate lymphoid cells which causes production of IL-23

• Pro-inflammatory cytokine

What is produced when anti-inflammatory bacteria are sensed via TLRs and NLRs?

Activation of Treg cells which causes production of IL-10

• Anti-inflammatory cytokine

What bacteria are reduced in IBD dysbiosis?

Firmicutes and Bacteroidetes are reduced

What bacteria are increased in IBD dysbiosis?

Enterobacteria

• Such as E. coli and Fusobacterium

Smoking can make Crohn’s disease better. True or False?

False.

Smoking can cause a worse disease course and can increase risk of recurrence after operation

It is ulcerative colitis which can be improved by smoking (weirdly)

Faecal Microbiota Transplants can be used in ulcerative colitis to help improve inflammation. However, they are not used in practice. Why?

Patients would need a FMT enema every day for two months

• This is way too intensive of a treatment for most people