The microbiome of the liver Flashcards
(39 cards)
How many bacterial species do humans carry?
10 trillion
How does the collective number of bacterial genomes compare to humans?
10:1
How many different species of bacteria/fungi/viruses exist?
> 1000
What did the discovery of the microbiome lead to?
The field of epigenetics
How many bacterial phyla are known?
Over 50
How many bacterial phyla are found in the gut?
6
List the 6 bacterial phyla found in the gut
Bacteroidetes
Firmicutes
Actinobacteria
Proteobacteria
Verrucomicrobia
Fusobacteria
Compare the number of genes found in the human genome and the human microbiome
23 000 genes in human genome
+ 1 000 000 genes in human microbiome
Microbial species and abundance stays the same throughout the GI tract
TRUE or FALSE
FALSE
Microbial species and abundance change over the length of the GI tract
Where are most of the bacteria found in the gut?
In the colon
What happens to the abundance of bacteria as you go further up the GI tract?
Decreases
The more - the microbiota, the better
Diverse
What is a major risk factor for cirrhosis?
Alcohol
Healthy individuals who consume alcohol show evidence of bacterial translocation
The relative abundance of phyla at most sites tends to be consistent across individuals
TRUE or FALSE
TRUE
Where is the composition of microbiota more variable between individuals?
Vaginal microbiota
Which phyla predominate in the colon?
Bacteroidetes
Firmicutes
What is dysbiosis?
Perturbation in composition, function or organisation of the microbiota
Related to various conditions
Which factors contribute to dysbiosis?
Environmental factors
Age
Genetics
What are the main consequences of liver disease?
Hepatic encephalopathy
Ascites
Spontaneous bacterial peritonitis
How do we know that bacteria play an important part in the progression of liver disease?
Patients positive for bacterial DNA in the blood have decreased survival of liver disease
Bacterial population in patients with liver disease is markedly different to controls
What is an important factor about the role of bacteria in liver disease?
The role changes depending on the stage of liver disease
Initially = progression of cirrhosis and fibrosis
Once the patient develops cirrhosis = increases chances of developing hepatic encephalopathy and spontaneous peritonitis
Examplea of how bacterial populations are different in liver disease patients compared to control
Less diversity
Abnormal bacterial species found in the gut - bacteria from mouth found in the liver
Increased population of ammonia-producing bacteria
How is the innate immune system linked to cirrhosis?
PAMPs and DAMPs activate immune cell receptors
These lead to the assembly of the inflammasome
Activates CASP-1 and leads to secretion of cytokines
Which inflammasome is thought to be activated in liver disease?
AIM2 inflammasome