To repeat, that’s 42% of people in the US think that they can survive without a liver. This shocking statistic, which was derived from a survey of 511 people representative of US households, highlights a deficit in awareness of the vital, multifunctional role the liver has in the body. A deficit that could be costly to many, considering that it is not just alcohol that can cause liver damage - many common and controllable diseases such as obesity, high cholesterol and type 2 diabetes can put liver health at risk.
In the past, a stigma was attached to liver cirrhosis – the scarring and deterioration of the liver – because it can be caused by alcohol abuse. However, there are a plethora of other diseases – including PSC – that can lead to liver cirrhosis. What’s more, not all of them are as rare as PSC, and many of them can remain silent for years, quietly causing damage. Liver cirrhosis can be caused by hepatitis B or C infection, as well as genetic diseases such as Alpha-1 Antitrypsin Deficiency.
One cause of cirrhosis that should be of special concern is non-alcoholic steatohepatitis (NASH), the accumulation of fat in the liver that causes liver damage in people who drink little or no alcohol, who do not have a hepatitis infection and have no known genetic disease. While the cause of NASH is unknown, both NASH and fat accumulation in the liver in general are on the increase, possibly due to rising rates of obesity.
Fat accumulation in the liver in people who do not abuse alcohol (also known as non-alcoholic fatty liver disease) is common – occurring in about 20-30% of western populations – and on its own it may be harmless. However, in 2-3 % of the population, for unknown reasons liver fat accumulation develops into NASH, in which the build-up of fat leads to inflammation and damage that can cause to cirrhosis. Despite this, patients may feel fine until liver damage reaches a critical level. This is why liver function tests are included in routine tests ordered by doctors. Checking liver function is just as important as checking blood pressure.
Liver health may be harder to understand or relate to than the support of the heart, lungs, or even the kidneys, but the liver works just as hard to keep the body alive. Not only does the liver remove harmful toxins and old red blood cells from the body, but it produces proteins that allow the blood to clot upon injury, stores energy, produces molecules that help you digest food and converts consumed carbohydrates, fats and proteins into useful energy sources for the rest of the body. The liver also stores vitamins and minerals and removes hormones circulating in the blood to keep them at safe levels. Cells in the liver known as Kupffer cells also contribute to immunity by removing pathogens and debris from the blood, while hepatocytes (the main cells in the liver) also secrete a protein called albumin into the blood to maintain fluid balance across blood and tissues.
When liver cirrhosis occurs, an individual may bruise or bleed easily, appear jaundiced, and experience intense itching and fluid retention in the legs or abdomen. When the liver fails, the first signs are normally nausea, loss of appetite, fatigue, and diarrhea, and as toxins build up in the blood stream, liver failure can eventually cause loss of brain function (hepatic encephalopathy). Without the liver, the body soon dies from a lack of energy, nutrients, and toxin removal.
Why should people interested in PSC care about NASH? Well, for one thing, all diseases that cause liver failure place a burden on the donor organ supply for liver transplants. NASH can be prevented by combatting obesity. It’s important for all of us to educate ourselves about the negative impact of obesity on our health and that of our loved ones, then do what we can to reduce our risk for metabolic disease, including NASH.
Another reason to care about NASH: it effects a lot of people, so there is a big market for drug development around NASH. Many anti-fibrotic and anti-inflammatory drugs developed for NASH find their way into the PSC testing pipeline. The opposite is also true: because PSC is a rare disease, it is an attractive gateway condition for getting FDA approval of a liver anti-fibrotic or other medication that may go on to be tested and approved in a larger market of NASH patients.
Your liver does so much to keep you energized and well, a silent but vital part of the machinery that keeps each of us alive. Give the liver the love it deserves – and share this information with others so they can do the same!