Cystic Fibrosis and Diabetes Connection Explained by Gene Mutation

People with cystic fibrosis can be prone to developing diabetes. However, only recently have researchers learned that the onset of diabetes occurs due to a mutation in a molecular mechanism that increases the risk of developing the disease. As a result, researchers from Lund University in Sweden and Karolinska Institutet have ended the myth that diabetes in patients with cystic fibrosis was caused by abnormalities in the pancreas, according to a recent press release.

“The increased risk of diabetes has previously been explained by the fact that cystic fibrosis causes damage to the pancreas, where the blood-sugar regulating
 hormone insulin is produced. We are the first research group to show that the mutated gene that causes cystic fibrosis also plays an important role in the release of insulin. The risk of diabetes is not only explained by the destruction of the pancreas,” said Anna Edlund, a doctoral student at Lund University Diabetes Centre.

Researchers have discovered that the mutation in the cystic fibrosis gene decreases the secretion of insulin into the blood. Therefore, the level of insulin in the body becomes insufficient when there is a greater need, such as after meals. This constitutes an additional problem since “cystic fibrosis is a severe health condition and diabetes exacerbates an already problematic situation,” according to Malin Flodström-Tullberg, a researcher at the Centre for Infectious Medicine, Karolinska instituter.

Usually insulin is released in two stages. The early stage is a rapid response to raised blood sugar and the later stage restores blood sugar levels. In cystic fibrosis, the early stage is particularly insufficient. “Our results also correspond to clinical observations. Many patients with cystic fibrosis who do not have diabetes have normal blood sugar in a fasting state, but raised blood sugar after a meal,” explained Anna Edlund.

Researchers analyzed the cells that produce insulin and were able to identify the cystic fibrosis gene effect during the insulin release process. When exposed to high glucose levels, the cells increased the insulin secretion as expected. However, with the presence of the cystic fibrosis gene, obstructing the ion channel, the release fell significantly. The study was performed in mice and in deceased donors.

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“Despite being common among cystic fibrosis patients, surprisingly little is known about the mechanisms behind diabetes in this group of individuals. We
need to know what causes the problem in order to develop preventive treatments that improve the cells’ ability to secrete insulin. Our study provide a first
piece of increased understanding how CFTR contribute to insulin secretion,” said Lena Eliasson, Professor at Lund University Diabetes Centre.

Cystic fibrosis occurs when there is a genetic mutation in the ion channel that controls the salt transportation in cells, mainly in the lungs and pancreas. Since patients produce an abnormal amount of mucus, their airways are more sensitive to infections. Other serious symptoms include diarrhea and poor weight gain, which are the result of a delayed secretion of pancreatic juice to the intestine. When it isn’t properly treated, the disease can be fatal. However, with the treatment developments most of the patients now live beyond the age of 40.