A SPECIES of tiny fish could hold the key to a breakthrough in treatment for a condition that affects more than 12,000 people in Scotland.

Researchers in Edinburgh studied zebrafish and discovered how brain cells which are damaged in people with Parkinson’s disease can be regenerated.

Their findings offer clues that could lead to treatments for the neurological condition, which causes movement problems and tremors. There are over 12,400 sufferers in Scotland, a figure that is predicted to rise by 40% in the next 20 years.

Parkinson’s occurs when specialised nerve cells in the brain are destroyed. These are responsible for producing an important chemical called dopamine.

When they die, or become damaged, the resultant loss of dopamine causes the impairment of body movements, and once the cells are lost from the human brain, they can neither be repaired nor replaced.

However, researchers discovered that in zebrafish, dopamine-producing nerve cells are constantly replaced by dedicated stem cells in the brain.

The team, led by the University of Edinburgh, also found that the immune system plays a significant role in this process.

In some regions of a zebrafish’s brain, though, the process does not work.

Researchers say that understanding the immune signals that facilitate replacement of these nerve cells could hold vital clues to developing treatments for humans.

The study was published in the Journal of Neuroscience.

Dr Thomas Becker, of the University of Edinburgh’s Centre for Discovery Brain Sciences, said: “We were excited to find that zebrafish have a much higher regenerative capacity for dopamine neurons than humans.

"Understanding the signals that underpin regeneration of these nerve cells could be important for identifying future treatments for Parkinson’s disease.”

Annie Macleod, Scotland director of Parkinson’s UK, said: “Currently there is no treatment that can slow, stop or reverse the loss of precious dopamine-producing brain cells in Parkinson’s, a neurogenerative condition that affects more than 12,400 people in Scotland. Treatments that could help replace the cells that have been lost and reverse Parkinson’s many symptoms hold the potential for giving back quality of life.

“This new discovery suggests the immune system plays a role in replacing brain cells. This could help point a way towards replicating the regenerative powers of the zebrafish in people. It is from early discoveries like this that we can see real promise for a future where we can put an end to Parkinson’s for good.”