Summary: Most people with Parkinson’s disease experience a reduced sense of smell years before movement symptoms appear. Researchers are investigating whether the neurons that carry scent information from the nose to the brain contribute to the disease’s development.
Source: University of Ottawa
More than 80 percent of people with Parkinson’s disease report a diminished sense of smell—often long before tremors, stiffness, or other motor symptoms begin.
A Canadian-led international research team has received a US$9 million grant from the Aligning Science Across Parkinson’s (ASAP) initiative to explore whether olfactory neurons—the scent-processing nerves that connect the nasal cavity to the brain—play a role in the origins and progression of Parkinson’s disease.
“Current therapies can alleviate many symptoms, but we still lack treatments that stop or slow Parkinson’s disease,” said team leader Dr. Michael Schlossmacher, a neurologist and Bhargava Family Research Chair in Neurodegeneration at The Ottawa Hospital. “This funding allows us to examine an understudied yet potentially critical route by which Parkinson’s could begin and spread, which may point toward new strategies for early intervention and prevention.”
The research team, which brings together specialists from Canada, Germany and the United States, will investigate links among environmental exposures in the nose, local inflammation, odor-processing brain regions and Parkinson’s-related genes. They will pursue these questions using both animal models and human samples to better understand mechanisms that could underlie disease initiation and progression.
A central hypothesis is that certain environmental triggers—viruses or other inhaled agents—might provoke a chain reaction within odor-sensing cells. That reaction could lead to the accumulation of alpha-synuclein, a protein that forms pathological clumps in Parkinson’s disease. “If alpha-synuclein aggregation begins in the olfactory epithelium, these abnormal protein assemblies could propagate along neuronal connections and gradually involve deeper brain regions linked to Parkinson’s,” Dr. Schlossmacher explained.
The team will combine molecular studies, imaging, and functional assays to trace how changes in the nasal cavity might influence brain circuits over time. They will also examine genetic and environmental risk factors that could make some individuals more susceptible to olfactory-driven disease pathways. By integrating findings from laboratory models with analyses of human clinical samples, the researchers aim to clarify whether the nose-to-brain route contributes meaningfully to Parkinson’s onset and progression.
Co-investigators include Dr. Brit Mollenhauer and Dr. Christine Stadelmann from University Medical Center Goettingen, Dr. Ben Arenkiel from Baylor College of Medicine and Texas Children’s Hospital, and Dr. Maxime Rousseaux from the University of Ottawa. Additional collaborators on the grant are Dr. Zhandong Liu (Baylor College of Medicine), Dr. Natalina Salmaso (Carleton University), Dr. Josef Penninger (University of British Columbia), Dr. John Woulfe (The Ottawa Hospital and University of Ottawa) and Dr. Subash Sad (University of Ottawa).
“If Parkinson’s begins in the nasal cavity, we may be able to detect early molecular signals in nasal secretions,” said Dr. Mollenhauer, neurologist and associate professor at University Medical Center Goettingen. A reliable fluid-based biomarker from the nose would be valuable for earlier diagnosis, for monitoring disease progression, and for improving the design and evaluation of clinical trials for new Parkinson’s treatments.
The project is aligned with ASAP’s emphasis on collaborative, open science. Team members plan to publish their results in open-access journals and to share data, methods and protocols widely and early. “We will make our protocols and datasets available before formal publication, and actively participate in the ASAP collaborative network,” said Dr. Julianna Tomlinson, scientific program manager for the international team and co-director of research in the Schlossmacher Lab.
By focusing on the olfactory system—the nasal cavity, scent-sensing neurons and connected brain regions—this research could clarify an important, early piece of Parkinson’s disease biology. Improved understanding of how environmental exposures, inflammation and genetic risk intersect in the nose and brain may open new avenues for early detection, preventive strategies, and treatments aimed at halting disease before it advances.
About this Parkinson’s disease research news
Author: Paul Logothetis
Source: University of Ottawa
Contact: Paul Logothetis – University of Ottawa
Image: The image is in the public domain