Diabetes drug could delay symptoms of Huntington’s disease

A drug used to treat type 2 diabetes may have therapeutic benefits for people experiencing the early symptoms of Huntington’s disease, researchers at the School of Medicine have discovered.

Researchers at the School, working with colleagues in Germany, found that the drug metformin can help to restore brain activity before symptoms of the terminal illness become established.

In research published in the journal eLife, the Dundee team found that the drug can help to regulate the Huntingtin protein, which in a mutated form can accumulate in the brain, leading to the onset of the Huntington's disease.

Dr Ros Langston, co-author of the study, said, “This is a really important development as there are currently no effective treatments for Huntington’s patients. This is a condition that affects thousands of people throughout the United Kingdom and this research suggests that there is a way we can help those who are destined to be affected by this disease.

“Metformin is already in the public domain and its limited side effects are already known, meaning that further studies should not take as long as those for new drugs. This means that in terms of developing therapeutic treatment for people who may have Huntington’s in their family, this is potentially very exciting news.”

Huntington’s disease is a degenerative condition that prevents parts of the brain from functioning correctly. Symptoms of the inherited illness usually appear between the ages of 30 to 50, and include involuntary movements of the limbs and body and cognitive impairment. Full-time nursing is required in the later stages of the disease, which is often fatal within two decades of the symptoms first appearing.

Dundee academics, working with counterparts based at Johannes Gutenberg University in Mainz, and the German Center for Neurodegenerative Diseases in Bonn, studied brain patterns and neural network activity in mice treated with Metformin, a commonly used medication by patients with Type 2 Diabetes.

Focusing on the visual cortex, the part of the brain that processes images from the retina and one of the first parts of the body to be affected by the 'very far from onset' (VFDO) stages of Huntington’s, researchers found that metformin helped to restore brain activity patterns and reduce erratic behaviour by controlling the Huntingtin protein, which is mutated in Huntington’s disease.

Professor Susann Schweiger-Seemann, Honorary Professor at Dundee and Speaker in Translational Neurosciences at Johannes Gutenberg University, said, “Metformin has been used to treat type 2 diabetes for around 20 years, is relatively cheap and has little in the way of side effects.

“By the time the symptoms of Huntington’s begin, it is too late to revive those brain cells that have already been affected, but our research has shown that metformin can reduce mutant Huntingtin proteins already at very early, pre-symptomatic disease stages, which could dramatically help to delay onset of the condition.

“We have to do more studies to see what happens with later onset symptoms, but from this study we have seen that Huntingtin protein levels dropped dramatically by taking metformin.”

The published paper can be found online.