Parkinson’s disease is a growing public health concern worldwide. Since the turn of the century, its prevalence has doubled, and according to the World Health Organization (WHO), the disease caused 329,000 deaths in 2019—an astonishing 100% increase in just two decades. The primary risk factors are aging and genetics, and as global populations continue to grow older, Parkinson’s cases and fatalities are expected to rise dramatically.
The struggle with Parkinson’s is deeply personal for many. For Mart Saarma, a neurobiologist and professor at the University of Helsinki, it hit home when his uncle was diagnosed with the disease. Saarma watched as his uncle’s condition slowly deteriorated, transforming his once-vibrant personality into someone unrecognizable. It was heartbreaking to witness, especially when his uncle, unable to recognize Saarma, once called the police, thinking a stranger had broken into his home. Such moments starkly illustrate the toll this disease takes—not just physically but emotionally—on patients and their families.
“People have understood how important it is to fight cancer, and thanks to that, we have started to get the first efficient cancer drugs,” says Saarma. “Unfortunately, this has not been the case with neurodegenerative diseases.”
The consequences are clear. Parkinson’s now affects 10-12 million people globally, and this figure is expected to double within the next 20 years. Saarma stresses that we must take this threat seriously, as it poses a significant and growing challenge for Western societies.
New Hope: The Fight for Funding and Treatment Innovation
Despite the rising prevalence, funding for neurodegenerative disease research has lagged, particularly compared to cancer. However, awareness is growing, and so is investment. Last year, GeneCode, a pharmaceutical company where Saarma serves as the chief science officer, secured a record-breaking €16 million in funding from the European Innovation Council Accelerator. The funds are earmarked for developing a groundbreaking drug to treat neurodegeneration in Parkinson’s patients.
In a recent conversation with Freethink, Saarma expressed cautious optimism about the drug’s potential. Preliminary evidence suggests that, unlike current treatments, this novel drug might not only alleviate symptoms but also protect neurons from further damage, potentially even restoring them.
The Challenge of Neuron Death
Why has progress in treating Parkinson’s been so slow? One reason is the complexity of the brain. The human brain houses roughly 100 billion neurons, each of which forms thousands of unique connections with other neurons, creating a web of communication essential for brain function. Unlike many other cells in the body, neurons don’t regenerate. Once a neuron dies, it’s gone for good.
In Parkinson’s disease, neurons in the substantia nigra, a structure located in the midbrain, begin to die. These neurons produce dopamine, a neurotransmitter vital for motor control and other bodily functions. When dopamine levels drop, the intricate balance of brain and body coordination falters. This results in the familiar tremors, spasms, and stiffness that plague Parkinson’s patients, but it can also lead to other symptoms like insomnia, depression, and even dementia.
Saarma likens dopamine to a symphony conductor. When dopamine levels are stable, the body’s movements and functions work in harmony. But Parkinson’s robs the brain of its conductor, throwing this symphony into chaos.
Levodopa and the Blood-Brain Barrier
The most common treatment for Parkinson’s is levodopa, a drug that replenishes dopamine in the brain. While it can help manage symptoms, it doesn’t prevent further neuron degeneration. Moreover, it has its downsides, including side effects like nausea. One of the reasons treatment options are so limited is the blood-brain barrier, a protective shield that prevents foreign substances—including potentially life-saving drugs—from entering the brain.
“None of the available drugs can slow down or stop the degeneration and death of these neurons,” says Saarma. The challenge, he explains, is developing treatments that can both penetrate the blood-brain barrier and halt the progression of neurodegeneration.
A Promising Approach: Neurotrophic Factors and GDNF
Some treatments have focused on neurotrophic factors, proteins that help neurons survive by activating protective mechanisms. Saarma’s research has shown promising results using a specific protein called GDNF, which has been shown to reverse Parkinson’s in animal models. However, these proteins are too large to pass through the blood-brain barrier, meaning they must be administered directly into the brain through surgery—a risky and invasive procedure.
GeneCode is developing a solution to this problem. Their drug is a "GDNF mimetic," which mimics the effects of neurotrophic factors while being small enough to pass through the blood-brain barrier. This could potentially allow earlier intervention, giving patients a better chance at maintaining a higher quality of life for longer.
The Path to a Breakthrough
While early results from animal studies have been promising, drug development is a long, arduous process. GeneCode is nearing the end of its animal experiments, after which the drug will undergo toxicology studies and human clinical trials.
Saarma remains pragmatic about the road ahead. While the drug shows great promise, the complexity of the human brain means that success is not guaranteed. Still, Saarma is optimistic that this and other collaborative efforts will push the boundaries of Parkinson’s treatment and give patients more hope than ever before.
Even if GeneCode’s drug does not ultimately succeed, the lessons learned from this international collaboration, involving labs across Europe and the United States, will undoubtedly contribute to the ongoing battle against this debilitating disease.
As Saarma says, “The field is endless, but my life is limited, as are all of ours. But you do what you can with your time.”
The rise of Parkinson’s disease presents a critical challenge, but with researchers like Saarma and companies like GeneCode at the forefront, there is hope that a new era of treatments may finally bring relief to millions of patients worldwide.