NAFLD: The Liver and Diabetes L12 Flashcards
Above what BMI value is considered obese?
>30
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As an individual gains weight, the risk of any of the consequences rises dramatically.
There is a near exponential positive relationship between BMI and diabetes risk. Though this only occurs once our body reaches a certain weight; it seems that we have a threshold and once it is passed our risk factors dramatically increase.
Define non-alcoholic fatty liver disease (NAFLD).
Give alcohol intake values for the disease to be considered caused by factors other than drinking.
Liver disease that has nothing to do with alcohol consumption.
By Definition, a women may not drink more than 20g of alcohol a day (2 units) and a man may not drink more than 30g a day (3 units).
State and define the progressive stages of NAFLD.
The different stages of the condition = Steatosis –> NASH –> Cirrhosis
Steatosis = Fat in the liver
NASH = Fat and inflammation in the liver
Cirrhosis = bad scarring of the liver
Steatosis –> NASH = __1__% of individuals progress.
NASH –> Cirrhosis = __1__% of individuals progress.
- 10
Virtually every population that NAFLD has been examined in, between 20%-__1__% of the population have some degree of NAFLD.
Examinations are primarily done by ____2____.
- 30
- Scanning
The main predictor of long term NAFLD outcome is not the presentation of the biopsy, but the amount of ______ that is present in the biopsy.
Fibrosis
The movement between steatosis and NASH is ______, in that individuals are likely to be moving back and forth between the 2.
Dynamic
State the 2 ways fat content in the liver can increase.
Can import fatty acids into the liver (either from diet or fat stores in adipose tissue).
Can synthesize fatty acids from carbohydrates from the diet.
State the 2 ways to decrese fat content in the liver.
Can esterify the fat into triglycerides and export it as VLDL (cholesterol).
Can burn it within the liver for energy (different types of oxidation).
In diabetics/insulin resistance there is a disconnect between peripheral tissues (muscles and adipose tissues) in that they ignore the ____1____ from the insulin. What happens is that HSL (hormone sensitive lipase) is dis-inhibited causing the flooding of fatty acids into the liver.
But the liver itself remains relatively sensitive to insulin signalling. So as the peripheral insulin resistance causes an influx of FFA’s into the liver, the ____2____ insulin and glucose levels in the blood are driving further ____3____ of fatty acids. = perfect storm of more fatty acids flowing to the liver and more fatty acids being made in the liver.
The liver tries to deal with the fatty acids and it starts to partition them towards ____4____. This is the fat we see when we look down the microscope.
- Signal
- High
- Synthesis
- Triglycerides
It has been suggested that it is a simple 2-headed hypothesis for NAFLD.
- Fat build-up in the liver
- Inflammation and scarring in the liver
It would therefore be tempting to think that if we could inhibit this transfer of fatty acids to triglycerides, we would stop the fat accumulation and cure NAFLD.
But scientists have tried this: They used a diet called the MCD diet, to induce fat accumulation in the liver. They then used ____1____ (so RNA silencing) to inhibit the enzyme DGAT2 (the key enzyme in the fatty acid esterification step). What they found was that by doing this they reduced the fat levels in the liver but they saw that the serum ALT levels (which are a ____2____ for liver damage, and are 20-30 in a healthy individual) shot up to 1800 in the mice. Also they saw lots of lipid oxidation so in other words, ______ 3 ______ damage to the liver cells. They saw this damage again when they measure TBars (another marker for oxidative stress in the liver).
So what has happened?
Well if you inhibit the synthesis of triglycerides, the fatty acids are pushed towards fatty acid oxidation. And it is this oxidation that releases lots of the chemicals that actually damage the cells. This ______ 3 ______ combined with lipotoxicity, ER stress, neutrophil recruitment, necrosis and apoptosis drives the formation of ____4____ in the liver.
- siRNA
- Marker
- Oxidative stress
- Fibrosis
Fatty liver disease is also a marker of an increased chance of ____1____ and ____2____.
In fact more people with NAFLD will die of ____1____ and a ____2____ than liver failure or liver cancer.
- CVD
- Stroke
NAFLD is a marker for the increased risk of HCC, which is what?
Hepatocarcinoma (liver cancer)
List the 3 gene alleles linked to increased NAFLD risk by GWAS studies.
PNPLA3
rs738409
TM6SF2