Chronic liver damage can result in the replacement of normal liver tissue with non-functioning scar tissue. Advanced liver damage is called cirrhosis, and glucose intolerance is a common feature of this condition. An article in the January 2009 issue of the “World Journal of Gastroenterology” reports that greater than 90 percent of people with liver cirrhosis are glucose intolerant, and nearly 30 percent will develop diabetes. Liver cirrhosis is irreversible and can be the result of alcoholic liver disease, hemochromatosis, non-alcoholic fatty liver disease or chronic hepatitis C infection.
Muscle Insulin Resistance
The liver is the primary disposal site of insulin; when the liver is damaged, less insulin is taken up and degraded, causing a condition of chronic hyperinsulinemia. A study in the July 1998 issue of “Hepatology” reports that hyperinsulinemia in patients with liver cirrhosis causes muscle insulin resistance. Another study in the March 1994 issue of “Hepatology” reports patients with cirrhosis exhibit metabolic abnormalities consistent with muscle tissue insulin resistance. This means that in people with impaired liver function, glucose is not as efficiently removed from the blood by muscle tissue, leading to a chronic elevation of blood glucose levels.
Liver Insulin Resistance
In people who have cirrhosis, insulin resistance eventually develops in the liver also. When the liver is less sensitive to insulin, it is no longer as effective in removing excess glucose from the blood or in converting glucose into the glucose-storage molecule, glycogen. As a result, blood glucose levels are higher, especially after a meal.
Chronic insulin resistance and the resultant high circulating levels of glucose and fats eventually destroy the insulin-secreting cells, called islets, in the pancreas. This leads to the development of overt diabetes where insulin levels are insufficient to regulate glucose metabolism. The study in “Hepatology” also reported that insulin secretion is reduced in patients with cirrhosis, indicating islet injury.