A team of researchers from the University of Barcelona and the Bellvitge Biomedical Research Institute (IDIBELL) has identified a potential biomarker of Parkinson's disease progression. According to the new study, published in the NPJ Parkinson's Disease , patients with a slow progression of the pathology would have a significant increase in the levels of a molecule called ecto-GPR37 in the cerebrospinal fluid. The findings could have relevant implications for the treatment of patients with this neurodegenerative disease, which is characterised by movement disorders such as tremors, rigidity, slowness of movement or postural instability.Francisco Ciruela, professor at the Faculty of Medicine and Health Sciences of the UB and member of the Institute of Neurosciences (UBNeuro) and IDIBELL, explains that "what the study suggests is that this biomarker could be used to define whether the progression of the disease will be fast or slow. On a clinical scale, being able to perform this stratification is very important, because the management of patients with slowly progressive Parkinson's disease versus those with rapid progression involves a different clinical approach".
According to the researcher, patients with rapid progression have an accelerated onset and worsening of symptoms, motor fluctuations and complications, as well as an increased likelihood of cognitive impairment and psychiatric symptoms. In contrast, patients with slow progression have a gradual onset and progression of symptoms and can maintain higher levels of functional ability and for longer periods of time. In addition, they often have milder symptoms, especially in the early stages. "If the disease progresses rapidly, the prognosis is worse than if it progresses slowly, as it can be managed more like a chronic disease. Consequently, patients with a rapid progression require more complex clinical management than those with a slow progression, who have a better prognosis", says the UB professor, who led the study.
Researchers from the Spanish National Cancer Research Centre (CNIO); the Institute for Biomedical Research and Innovation in Cadiz; the Karolinska Institute (Sweden); the University of California (USA); and King's College London (UK) also participated in the study.
Study with patient samples from different neurodegenerative diseases
This research follows a 2021 study by the same research team, which found that ecto-GPR37, present on neuronal cells in the brain, could be a promising candidate diagnostic biomarker for Parkinson's disease. Ecto-GPR37 is a fragment of an orphan neuronal G protein-coupled receptor called GPR37. Although it is a Parkinson's-associated receptor, neither its neuronal function nor the endogenous ligand, i.e. the specific molecule to which it binds, is yet known.
To validate previous findings and test whether this potential biomarker is specific to Parkinson's disease, the researchers have now analysed the processing of GPR37 in the brain and the presence of ecto-GPR37 in the cerebrospinal fluid of patients with Parkinson's, Alzheimer's and also other neurodegenerative diseases with clinical features similar to Parkinson's, such as multiple system atrophy, corticobasal degeneration and progressive supranuclear palsy. The researchers note that, "despite the similarities, patients with these diseases have a different prognosis and do not respond to levodopa, the main treatment for Parkinson's disease. Therefore, the exploration of new biomarkers is essential to accurately stratify patients, especially in the early stages, when the diagnosis is more challenging".
