Neurons in the portion of the brain that governs movement that typically generate a substance called dopamine begin to die in Parkinson’s disease. This gradually leads to symptoms including tremors, stiffness, and problems with balance and coordination.
Some medications used to treat the illness increase dopamine levels. These can temporarily alleviate symptoms, but they do not delay disease development and eventually stop functioning. New Parkinson’s disease therapies are desperately required.
Drug research has been impeded by the lack of simple blood tests to identify Parkinson’s disease early, before substantial damage occurs. According to recent research, Parkinson’s disease is most likely a set of illnesses with various origins that end up inflicting comparable damage but may require different therapies.
Damage to neurons’ mitochondria—the organelles within cells that provide energy—is one possible cause of Parkinson’s disease in certain patients. An assay to identify persons whose condition is caused by mitochondrial damage would be required to properly evaluate medications that improve mitochondrial function.
An NIH-funded research team lead by Dr. Laurie Sanders of Duke University developed a blood test to identify damage to the DNA in mitochondria, known as mtDNA, in a recent study. They based its Mito DNADX test on polymerase chain reaction, or PCR, technology. The findings were published in Science Translational Medicine on August 30, 2023.
Initial results shown that Mito DNADX could identify mtDNA damage that other tests did not. The test then discovered that mtDNA damage was increased in blood cells from patients with Parkinson’s disease compared to people without the disorder.
Mito DNADX revealed mtDNA damage in persons with a rare genetic mutation known to cause Parkinson’s disease, as well as in people with the condition who did not have any known genetic risk factors. It worked whether or not patients were using Parkinson’s drugs at the time. The findings of the tests were likewise consistent over time. Finally, the researchers determined an mtDNA damage threshold value that successfully distinguished persons with Parkinson’s disease from healthy participants.
Further research revealed that aberrant activity of an enzyme known as LRRK2 kinase elevated levels of mtDNA damage. Reduced aberrant LRRK2 activity is now a therapeutic research target for Parkinson’s disease. As a result, Mito DNADX might be utilized to track therapy effects in real time.
“Our hope is that this assay will not only be able to diagnose Parkinson’s disease, but will also be able to identify drugs that can reverse or stop mitochondrial DNA damage and the disease process,” Sanders adds. “This disease wreaks havoc on people, and we’re still only treating the symptoms.” It’s critical to get novel, effective therapies to market.”
Additional study is required to verify the test in broader, more varied groups. Longer-term research is also required to determine if mtDNA damage varies as Parkinson’s disease advances. Furthermore, mtDNA damage is not limited to Parkinson’s disease. Researchers are developing new methods for diagnosing and tracking Parkinson’s disease that may be more specific to the condition.