How Alcohol Causes Liver Damage
direct toxicity of alcohol to the liver cells is the main cause of
the resulting liver cell damages, which leads to chronic liver
diseases. Epidemiological studies found that incidence of cirrhotic
liver diseases are closely related to alcohol consumption. In
countries where the average consumption of alcohol per capital is
over 10kg per year, the incidence rate of alcoholic liver diseases
was quite high. Consumption of alcohol was found to be related to
approximately one half to two-thirds of the cirrhotic conditions. In
addition, sporadic and heavy binge drinking was found to cause more
damage than moderate drinking on a regular basis. Acute hepatitis
can often occur if a chronic drinker has an extremely large amount
of alcohol. Liver failure can also occur in some rare cases. If a
normal person drinks an unusually large amount of alcohol within a
short period of time, the triglyceride in the liver can dramatically
increase five to 10 times and cause fatty liver deposits.
the alcohol enters the body, 95% of it will be metabolized in the
liver. Inside the liver cells, alcohol turns to acetaldehyde, which
is even more toxic to the liver than the original form of alcohol.
The alcohol and its metabolites cause the liver to become inflamed.
Long-term drinking causes the inflammation to become persistent and
leads to fibrosis and cirrhosis. In the cirrhotic stage, many
complications can happen and may even cause liver failure and death.
Acetaldehyde can combine with the liver cell membrane to form a new
antigen, which stimulates the immune system to produce autoimmune
reactions. The metabolism of alcohol can also cause unusually high
consumption of the oxygen, which becomes a metabolism disorder of
the liver. This in turn causes fat deposits, degeneration, and
necrosis of liver cells. The onset of inflammation leads to an
over-production of free radicals that can further damage liver cells
and impair their functions. Alcohol also reduces the production of
antioxidants, which are the body's natural defenses against free
radicals. If a patient is already infected with HBV or HCV, these
harmful effects will exacerbate the present liver inflammation and
progression of fibrosis can be accelerated dramatically.
top of exacerbating inflammation, acetaldehyde itself can also cause
fibrosis directly. One of the mechanisms that alcohol promotes
disease progression is by increasing the amount of certain
cytokines, such as TGFb1 (transforming growth factor-beta 1), PDGF
(platelet delivered growth factor), and PAI (Plasminogen activator
inhibitor). They activate the hepatic stellate cells (HSC) of the
liver and cause the cells to loss their vitamin A content, which
then begins to produce scar tissue. The activated HSC can also
constrict blood vessels, reducing the blood infusion to the liver
cells and decreasing the oxygen and nutrition supply to the liver
cells. The liver damage caused by alcohol is related to the length
of time and the quantity of alcohol consumed at a given time.