Scientists eliminate Parkinson's disease in mice generating new neurons

A breakthrough that led to the creation of new neurons in mice could be used to transplant brain cells in Parkinson's patients and cure them of the disease.

Researchers of University of California San Diego School of Medicine created neurons in mice using a new and much simpler method which involves rewriting genes, the study has been published in Nature on June 24. 

Parkinson's disease is characterised by a loss of dopaminergic neurons in a region of the brain responsible for reward and movement - replacing those cells could help to reduce or even reverse the symptoms of the degenerative disease.

A small study involving mice with Parkinson's saw those given the 'new neuron treatment' return to normal within three months and stay disease free for life.

The researchers said it could one day be used to 'cure' any disease caused by the loss of neurons but warned saying, "it's was a long way off" and hadn't been tested yet. 

Xiang-Dong Fu and his team claimed certain brain cells called astrocytes can be turned into functional dopaminergic neurons, according to their study. 

Although the research is on early stage, but these newly produced brain cells could one day be implanted into a Parkinson's patient to help their condition.

'It's my dream to see this through to clinical trials, to test this approach as a treatment for Parkinson's disease, but also many other diseases where neurons are lost, such as Alzheimer's and Huntington's diseases and stroke,' said Xiang-Dong Fu , the lead researcher of this project. 

'Researchers around the world have tried many ways to generate neurons in the lab, using stem cells and other means, so we can study them better, as well as to use them to replace lost neurons in neurodegenerative diseases. The fact that we could produce so many neurons in such a relatively easy way came as a big surprise,' he added. 

Astrocytes produce a protein which prevents them from becoming neurons but by removing this protein they are converted into fully functional neurons. 

As part of this study the team found new neurons can repopulate circuits in the brain, restore dopamine levels and rescue motor function in mice with Parkinson's. 

But they caution that further research is needed before the approach can be applied to humans as it has only been studied in mice brains.

The researchers administered the treatment directly to a part of the mouse's brain, which is responsible for regulating motor control and reward behaviour including to the part of the brain that typically loses dopamine-producing neurons in Parkinson's disease.

A control group of mice received mock treatment without any new neurons.

In the treated mice, a small subset of astrocytes converted to neurons, increasing the number of neurons by approximately 30 per cent, the study suggests.

Dopamine levels were restored to a level comparable to that in normal mice. By two different measures of limb movement and response, the treated mice returned to normal within three months after a single treatment.

They remained completely free from symptoms of Parkinson's disease for the rest of their lives but the control group showed no improvement.

Professor Tara Spires-Jones of the UK Dementia Research Institute at the University of Edinburgh and deputy director of the Centre for Discovery Brain Sciences, University of Edinburgh, said the study shows remarkable promise.

'It is important to note that it was conducted in mice with group sizes from three to eight and there is a long way to go to translate this into a treatment for people.'

Robert Howard, professor of old age psychiatry, at University College London, said the findings were an 'extraordinary scientific discovery'.

He added, 'This opens up a completely novel avenue for development of treatments to 'rebuild' damaged brains in Alzheimer's and Parkinson's diseases.'