New Study Finds Potential Parkinson’s Disease Biomarker
Parkinson’s disease affects an estimated 4 million people worldwide, yet there is not a single clinical test available to effectively diagnose this widespread degenerative disease. While there are some tentative treatments which may be useful in treating Parkinson’s if caught early, there is little way to definitively diagnose the condition until late in it’s progression, when neurons have already been destroyed and motor symptoms such as tremors have already become evident.
However, the key to identifying Parkinson’s may be on the horizon. The Almagest reports researchers from Beth Israel Deaconess Medical Center (BIDMC) have discovered a possible biomarker for diagnosing Parkinson’s hiding just beneath the skin.
Their study, published in the journal Neurology, reports that heightened levels of the protein alpha-synuclein can be detected in the skin of Parkinson’s patients. This could be a potential sign that would allow clinicians to diagnose the disease at much earlier stages, allowing for more effective treatment.
“Even the experts are wrong in diagnosing Parkinson’s disease a large percentage of the time,” says senior author Roy Freeman, MD, Director of the Autonomic and Peripheral Nerve Laboratory at BIDMC and Professor of Neurology at Harvard Medical School. “A reliable biomarker could help doctors in more accurately diagnosing Parkinson’s disease at an earlier stage and thereby offer patients therapies before the disease has progressed.”
Alpha-synuclein is a protein typically found throughout the nervous system. Researchers have yet to identify its function, but it is a primary component of protein clumps known as Lewy bodies, considered to be a signature component of Parkinson’s.
“Alpha-synuclein deposition occurs early in the course of Parkinson’s disease and precedes the onset of clinical symptoms,” explains Freeman, who with his coauthors suspected that the protein was elevated in the skin’s structures with autonomic innervation.
“Symptoms related to the autonomic nervous system, including changes in bowel function, temperature regulation, and blood pressure control may antedate motor symptoms in Parkinson’s patients,” he explains. “Skin-related autonomic manifestations, including excessive and diminished sweating and changes in skin color and temperature, occur in almost two-thirds of patients with Parkinson’s disease. The skin can provide an accessible window to the nervous system and based on these clinical observations, we decided to test whether examination of the nerves in a skin biopsy could be used to identify a PD biomarker.”
The study enlisted 20 Parkinson’s disease patients, along with 14 control subjects of similar age and gender. The participants underwent examinations, autonomic testing and skin biopsies in three locations on the leg. According to the press release, alpha-synuclein deposition and density of cutaneous sensory, sudomotor and pilomotor nerve fibers were measures.
As the hypothesis predicted, the results showed that Parkinson’s patients had heightened levels of alpha-synuclein in the cutaneous nerves supplying the sweat glands and pilomotor patients. The higher the level of alpha-synuclein deposition found in the nerves supplying the skin’s autonomic structures was associated with more advanced Parkinson’s disease and worse motor functioning.
“There is a strong and unmet need for a biomarker for Parkinson’s disease,” says Freeman. “Alpha-synuclein deposition within the skin has the potential to provide a safe, accessible and repeatable biomarker. Our next steps will be to test whether this protein is present in the cutaneous nerves of individuals at risk for Parkinson’s disease, and whether measurement of alpha-synuclein deposition in the skin can differentiate Parkinson’s disease from other neurodegenerative disorders.”