Scientists at the University of Edinburgh have made a major new discovery that may bring them closer to reversing the damage caused by motor neurone disease (MND).

Motor neurone disease, also known as amyotrophic lateral sclerosis (ALS), is a rare condition that progressively damages parts of the nervous system, leading to muscle weakness, and often times visible wasting.

It occurs when the specialist nerve cells in the brain and spinal cord called motor neurones stop working properly, causing impaired muscle control which can affect one’s ability to walk, grip objects, speak, swallow and even breathe. There is currently no cure for MND.

This new study, published in the online journal Springer on January 4, has identified that damage to nerve cells caused by MND may be able to be repaired by improving the energy levels in mitochondria, which supplies power to the neurons.

Scientists used stem cells from people with the C9orf72 gene mutation that causes both MND and frontotemporal dementia to generate motor neuron cells in the lab and make this discovery. They also analysed human post-mortem spinal cord tissue from MND patients.

Scientists found that the axon, which is the long part of a motor neuron cell that connects to the muscle, is shorter in human stem cells of MND patients compared to healthy cells.

They also found that this was caused by a defective energy supply from the mitochondria, and it affects the movement of the mitochondria as it travels up and down the axon, thus impairing its ability to do its job.

By boosting the mitochondria, however, the axon reverted back to normal. Drugs approved for other diseases may be effective in treating this issue, scientists argue.

“The importance of the axon in motor nerve cells cannot be understated,” said Dr Arpan Mehta, who led the study at Euan MacDonald Centre. “Our data provide hope that by restoring the cell’s energy source we can protect the axons and their connection to muscle from degeneration.

“Work is already underway to identify existing licensed drugs that can boost the mitochondria and repair the motor neurons. This will then pave the way to test them in clinical trials.”

Craig Stockton, the chief executive of MND Scotland, emphasised how exciting this breakthrough is. Researchers also hope that the findings could apply to those with other forms of MND.

“We look forward to seeing if these positive results can be replicated for patients,” he said. “Once researchers have identified a drug they believe could have the desired effect, this treatment could then be fast-tracked for human trials using the pioneering MND-SMART clinical trial platform – into which MND Scotland has invested £1.5m.

“Researchers, clinicians, charities and supporters are all working hard to take us closer to finding a cure and by joining together we’ll get to that day even sooner.”

Picture: University of Edinburgh

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