By Michelle Jaffee
Measuring the expression of two specific proteins in blood immune cells could provide a new way to monitor progression and treatment response in Parkinson’s disease, according to research by McKnight Brain Institute investigators published May 25. The team analyzed blood samples of a patient with a genetic mutation associated with the disease.
The study, in the Journal of Parkinson’s Disease, is the latest step in a line of research led by Adithya Gopinath, Ph.D., a graduate research assistant; Habibeh Khoshbouei, Pharm.D., Ph.D., a professor of neuroscience and psychiatry; Adolfo Ramirez-Zamora, M.D., division chief of movement disorders; Michael Okun, M.D., director of the Norman Fixel Institute for Neurological Diseases at UF Health; and UF neurogeneticist Matthew J. Farrer, Ph.D., a professor of neurology.
Khoshbouei’s lab previously discovered that in patients with Parkinson’s disease, there are significantly higher levels of two proteins, tyrosine hydroxylase (TH) and dopamine transporter (DAT), in blood immune cells compared to healthy individuals. Building on this discovery, the lab developed a blood test to measure DAT and TH levels in monocytes — a type of white blood cell — both in healthy individuals and in those with Parkinson’s disease. The researchers found that treatment with medication reduced these levels while lessening symptoms, though the data in the initial study represented TH and DAT levels at a single point in time.
The majority of Parkinson’s cases have an unknown cause and are referred to as idiopathic Parkinson’s. However, genetics drive disease risk about 10-15% of the time. For the new study, the team focused on a specific patient with a mutation in the TH gene. Over several months, they observed that levels of immune cells expressing TH and DAT both increased with the worsening of the patient’s symptoms, which included slowness, shuffling gait, lower extremity pain and impaired hand dexterity.
In addition, they observed that when the patient with the TH gene mutation was treated with medication, the number of DAT-expressing immune cells decreased but not the number of TH-expressing immune cells. By contrast, in 114 Parkinson’s patients with a normal TH gene, both types of immune cells were reduced significantly with medication, the researchers reported.
“These findings indicate that measuring DAT and TH expression in blood immune cells could be a valuable blood marker for tracking disease progression and treatment response in Parkinson’s disease patients,” Gopinath said.