Blood test to detect Parkinson’s disease could lead to earlier treatment

Australian researchers hope discovery can be used to diagnose disorder – now done through process of eliminationResearchers have developed the world’s first blood test that can detect the abnormal metabolism of blood cells in people with Parkinson’s disease, which means the blood test could be used to diagnose the disorder.

At present the only way to diagnose Parkinson’s disease, a degenerative neurological condition, is through ordering a range of tests and scans to rule out other disorders, combined with examining symptoms.

Patients are often diagnosed only after they have developed symptoms and brain cells have already been destroyed. While there is no cure for Parkinson’s, early detection allows treatment with medication and physiotherapy to begin, which may slow the deterioration of motor functions in patients.

Because diagnosing the disease is a process of elimination, and the symptoms mimic those of other neurological disorders, patients are also at risk being diagnosed and treated for the wrong disease.

The group of Australian researchers from La Trobe University believe their blood test will enable doctors to detect Parkinson’s disease with unprecedented reliability and lead to earlier treatment. Their findings are under review by an international medical journal.

The lead researcher on the study, Prof Paul Fisher, said the discovery turned conventional understanding about Parkinson’s on its head and had shocked the researchers.

It has been widely believed that a toxic buildup of byproducts that cause damage to brain cells and Parkinson’s disease were due to a defect in the cell’s mitochondria, where energy metabolism occurs. But Fisher and his team found through their blood tests that there was no damage to the mitochondria of patients with Parkinson’s disease.

“Based on the current literature we were expecting reduced oxygen consumption in the mitochondria, which leads to a build up of toxic byproducts, but what we saw was the exact opposite,” he said. “We were able to show the mitochondria were perfectly normal but were working four times as hard, which also leads to increased production of poisonous byproducts to occur.”

“So what has changed is our understanding of why these poisonous byproducts are being produced, which opens up new avenues for research into treatments.”

Fisher said so far, the blood test had been trialled on a small test group of 38 people (29 with Parkinson’s and a control group of nine healthy people), and had reliably detected the hyperactive mitochondria of Parkinson’s patients.

But the researchers have not had the funding to test whether this hyperactivity occurred exclusively in Parkinson’s patients or in all patients with neurological disorders, such as Alzheimer’s.

The US-based Michael J Fox Foundation for Parkinson’s Research and its local funding partner, the Shake It Up Australia Foundation, have granted La Trobe more than $640,000 to further develop the diagnostic blood test.

Fisher said the test could be available to the public in as little as five years if sufficient additional funds could be raised for its rapid development.

“We would love to be able to do a longitudinal study on people in their 40s who have not quite entered the age of high risk for Parkinson’s and predict whether they will get it or not and see if it can detect the disease before physical symptoms develop,” he said. “But we’d need thousands of patients and the corresponding funding.”

A neurologist, associate professor Simon Lewis, a world-leading Parkinson’s researcher with the University of Sydney’s Brain and Mind Centre, was not involved in the study but said if the test proved only able to diagnose those with established Parkinson’s it may not be very useful.

“What we’re really hoping for is something that can diagnose Parkinson’s at the earliest possible stage and in fact even before there are physical symptoms occurring,” he said.

“Currently, we are making the diagnosis based on the history from the patient and their family, from the physical examination, and then you have to exclude other diagnoses through scans and other tests. And we have nothing we can offer as a potential cure.

“So while it is great that a local research team has been able to secure this funding secure funding for exploring the merit in their approach, we can’t put the cart before the horse.”