200 years later, the search for a cure for Parkinson’s continues

On the surface, actor Michael J. Fox, singer Neil Diamond, civil rights activist Jesse Jackson and Scottish comedian Billy Connolly would appear to have little in common. Except for one thing. They all have Parkinson’s Disease (PD).

Their celebrity status has helped raise public awareness about the condition, but studies show that awareness doesn’t amount to an understanding of PD or the extent to which it impacts someone’s life. In fact a study in the UK found that many people still don’t think PD is a serious condition.

To try and help change that people around the world will be holding events today, April 11th, World Parkinson’s Day.

The disease was first described by James Parkinson in 1817 in “An Essay on the Shaking Palsy”. In the essay Parkinson described a pattern of trembling in the hands and fingers, slower movement and loss of balance. Our knowledge about the disease has advanced in the last 200 years and now there are treatments that can help slow down the progression of the disease. But those treatments only last for a while, and so there is a real need for new treatments.  

That’s what Jun Takahashi’s team at Kyoto University in Japan hope to provide. In a first-of-its-kind procedure they took skin cells from a healthy donor and reprogrammed them to become induced pluripotent stem cells (iPSCs), or stem cells that become any type of cell. These iPSCs were then turned into the precursors of dopamine-producing neurons, the cells destroyed by PD, and implanted into 12 brain regions known to be hotspots for dopamine production.

The procedure was carried out in October and the patient, a male in his 50s, is still healthy. If his symptoms continue to improve and he doesn’t experience any bad side effects, he will receive a second dose of dopamine-producing stem cells. Six other patients are scheduled to receive this same treatment.

Earlier tests in monkeys showed that the implanted stem cells improved Parkinson’s symptoms without causing any serious side effects.

Dompaminergic neurons derived from stem cells

Scientists at UC San Francisco are trying a different approach, using gene therapy to tackle one of the most widely recognized symptoms of PD, muscle movement.

In the study, published in the journal Annals of Neurology, the team used an inactive virus to deliver a gene to boost production of dopamine in the brain. In a Phase 1 clinical trial 15 patients, whose medication was no longer able to fully control their movement disorder, were treated with this approach. Not only were they able to reduce their medication – up to 42 percent in some cases – the medication they did take lasted longer before causing dyskinesia, an involuntary muscle movement that is a common side effect of the PD medication.

In a news article Dr. Chad Christine, the first author of the study, says this approach may also help reduce other symptoms.

“Since many patients were able to substantially reduce the amount of Parkinson’s medications, this gene therapy treatment may also help patients by reducing dose-dependent side effects, such as sleepiness and nausea.” 

At CIRM we have a long history of funding research into PD. Over the years we have invested more than $55 million to try and develop new treatments for the disease.

In June 2018, the CIRM Board awarded $5.8 million to UC San Francisco’s Krystof Bankiewicz and Cedars-Sinai’s Clive Svendsen. They are using neural progenitor cells, which have the ability to multiply and turn into other kinds of brain cells, and engineering them to express the growth factor GDNF which is known to protect the cells damaged in PD. The hope is that when transplanted into the brain of someone with PD, it will help slow down, or even halt the progression of the disease. 

The CIRM funding will hopefully help the team do the pre-clinical research needed to get the FDA’s go-ahead to test this approach in a clinical trial. 

David Higgins, CIRM Board member and Patient Advocate for Parkinson’s Disease

At the time of the award David Higgins, PhD, the CIRM Board Patient Advocate for Parkinson’s Disease, said: “One of the big frustrations for people with Parkinson’s, and their families and loved ones, is that existing therapies only address the symptoms and do little to slow down or even reverse the progress of the disease. That’s why it’s important to support any project that has the potential to address Parkinson’s at a much deeper, longer-lasting level.”

But we don’t just fund the research, we try to bring the scientific community together to help identify obstacles and overcome them. In March of 2013, in collaboration with the Center for Regenerative Medicine (CRM) of the National Institutes of Health (NIH), we held a two-day workshop on cell therapies for Parkinson’s Disease. The experts outlined the steps needed to help bring the most promising research to patients.

Around one million Americans are currently living with Parkinson’s Disease. Worldwide the number is more than ten million. Those numbers are only expected to increase as the population ages. There is clearly a huge need to develop new treatments and, hopefully one day, a cure.

Till then days like April 11th will be an opportunity to remind ourselves why this work is so important.

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