Parkinson’s disease may be the result of an energy crisis in brain cells that
have unusually high energy needs in order to control movement. The crisis causes the cells to overheat and burn
themselves out.
The researchers found that Parkinson’s disease arises in complex neurons with lots of branches that demand high levels of energy.
This was the finding of a new study led by researchers at the University of Montreal in
Canada reported in the journal Current Biology.
Lead researcher Louis-Éric Trudeau, a professor in pharmacology and neurosciences who has
spent the last 17 years studying the part of the brain that causes Parkinson’s disease,
schizophrenia and drug addiction, says:
“Like a motor constantly running at high speed, these neurons need to produce an
incredible amount of energy to function. They appear to exhaust themselves and die
prematurely.”
He hopes the findings will produce better ways to represent Parkinson’s disease in animal
models and lead to new treatments. He notes it is very difficult to reproduce symptoms of
Parkinson’s disease in mice, even when you insert human genes into their genomes.
This could then lead to discovery of drugs to help brain cells reduce their energy
consumption or use energy more efficiently, thus reducing the damage they accumulate over
time. The team is already pursuing this end.
Parkinson’s disease arises from the death of brain cells in a few restricted areas of the
brain, such as the substantia nigra. The brain cells affected by Parkinson’s disease release dopamine, a chemical messenger that
helps to regulate movement, emotional responses and other functions.
As the disease progresses, the amount of dopamine produced in the brain decreases and the
symptoms – which include tremor, slowness, stiffness and impaired balance – gradually worsen,
making it increasingly difficult to walk, talk, look after oneself and have a normal life.
Mitochondria ‘forced to work at burnout rates’
For the last 3 years, the team has been investigating why the mitochondria inside cells in
the areas of the brain affected by Parkinson’s disease work so hard and overheat. Mitochondria are tiny
powerhouses that produce the energy cells need to function, grow and release signals.
Fast facts about Parkinson’s disease
- An estimated 7-10 million people worldwide are living with Parkinson’s disease
- Men are 1.5 times more likely to have Parkinson’s than women
- Each person with Parkinson’s will experience symptoms differently.
Learn more about Parkinson’s disease
They discovered that the cells in these brain areas have very complex structures
with lots of branches and sites where the chemical messengers are released, and suggest it is
this complexity that demands high levels of energy.
Prof. Trudeau notes their findings support the idea that these complex neurons force their
mitochondria to work at burnout rates to meet their energy demands, which would explain their
accelerated deterioration.
“To use the analogy of a motor,” he says, “a car that overheats will burn significantly more
fuel, and, not surprisingly, end up at the garage more often.”
As we age, this complexity may also make the brain cells particularly vulnerable –
they are more likely to malfunction and die, triggering Parkinson’s disease, a condition that
predominantly strikes later in life.
Prof. Trudeau says as life expectancy increases, so does the challenge to find treatments
for neurodegenerative diseases like Parkinson’s, since:
“From an evolutionary standpoint, some of our neurons are perhaps just not
programmed to last 80, 90 or 100 years, as we are seeing more and more. It’s to be expected
that certain parts of our body are less able to withstand the effects of
time.”
But he is hopeful that because Parkinson’s disease only affects a limited part of the brain,
effective treatments will be found sooner rather than later.
Meanwhile, Medical News Today has also learned of another study that finds two
proteins may play a key role in the progression of
Parkinson’s disease. Researchers from The Rockefeller University and Columbia University in
New York say the two proteins appear to protect the brain cells most affected by Parkinson’s,
and the disease sets in when their activity declines.
Written by Catharine Paddock PhD
Copyright: Medical News Today
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