CM-Fatty Liver Disease and Cirrhosis Flashcards
Describe the pathological difference between a normal liver and fibrotic liver in terms of cells and extra-cellular matrix.
Normal and fibrotic livers have the same parenchymal (hepatocytes) and non-parenchymal (stellate, Kupffer, endothelial) cells.
The difference is that fibrotic livers have thick sinousoidal collagen instead of a thin basement membrane and increased interstitial collagen in the space of Disse
What cells are responsible for fibrosis in diseased livers?
Stellate cells- paracrine signals from Kupffer, endothelial, tumor and inflammatory cells active them to myofibroblasts.
Inflammatory cells are mitogenic to stellate cells meaning that they also stimulate them to proliferate
What determines whether a cell will go through apoptosis or necrosis?
If there is a lack of mitochondrial production of energy (usually due to lack of oxygen) the cell will undergo necrosis.
If there is adequate mitochondrial energy, caspase system will be activated and the cell will undergo apoptosis.
What histopathologic cells are associated with necrosis? apoptosis?
Necrosis- balloon degeneration
Apoptosis- councilman bodies
What inflammatory cells are associated with inflammation due to alcohol or fatty liver?
PMNs
What inflammatory cells are associated with viral, autoimmune or immunoallergic reactions?
lymphocytes
Describe the progression from chronic liver damage to cirrhosis.
Damage–> inflammation–> stimulates stellate cells–> stellate cells become myofibroblasts and proliferate–> interstitial fibrosis and subendothelial fibrosis–>bridging (P/P, CV/CV, P/CV)–> regenerating hepatocytes form distinct nodules within the fibrous bands = cirrhosis
Why does cirrhosis lead to portal hypertension?
What are the complications of portal hypertension?
The fibrosis and nodules distort normal architecture so there is increased resistance to flow (P-Q-R), and thus increased pressure.
This leads to:
1. varices (esophageal, caput medusa, hemorroids)
2. encephalopathy
3. ascites
What is the threshold of ethanol consumption per day needed for any liver disease to occur in women?
How many beers, wine, shots is that?
20 grams/day
Beer: 1-2
Wine 1-2
Liquor: 1-2
(technically about 1.5)
What is the threshold of ethanol consumption per day needed for any liver disease to occur in men?
How many beers (12), wine (5oz), or shots (1oz) is that?
Between 40 and 60 which translates to between 3 and 5 beers a day
What is required to develop alcoholic liver disease?
- alcohol consumption
- gender
- nutritional status
- Hep C or other co-infections
“malnutrition and alcohol consumption in susceptible individuals”
What is implicated in most of the toxic effects of alcohol on the liver?
Acetaldehyde- the first metabolite in the breakdown of alcohol that can covalently bind to proteins, lipids and DNA
What is the proposed mechanism by which alcohol causes hepatic steatosis?
- by-products of alcohol breakdown are substrates for triacylglycerol synthesis
- increases release of fatty acids from adipocytes which are taken up by the liver a reesterified into triacylglycerol
- decreased VLDL secretion
What are the main causes of NAFLD and secondary fatty liver disease?
NAFLD: obesity, diabetes, genetic and metabolic disorders, jejuno-ileal bypass, hyperlipidemia
Secondary fatty liver disease: drugs, toxins, HepC
Describe the progression spectrum of fatty liver in terms of histopathology.
- steatosis- fat w/o inflammation. fat droplets can be macrovesicular (typically) or microvesicular (Reyes, acute fatty liver of pregnancy)
- steatonecrosis - fat with inflammation
- PMNs & Mallory bodies = steatohepatitis
- Councilman bodies = apoptosis
- balloon degeneration = necrosis - Fibrosis and Cirrhosis