Parkinson’s News TodayMitochondrial Dysfunction Partly Explained by Immune Responses

A new study challenges previous assumptions about mitochondrial DNA copy numbers in Parkinson’s disease, suggesting that variations may reflect immune responses rather than mitochondrial dysfunction. This finding from researchers at The Walter and Eliza Hall Institute of Medical Research (WEHI) in Australia opens possibilities for developing blood-based diagnostic tests, potentially making Parkinson’s screening more accessible and cost-effective.

Key Points:

• The study analyzed data from two major databases – the Accelerating Medicines Partnership program for Parkinson’s Disease and the U.K. Biobank – revealing significantly lower mitochondrial DNA copy numbers in Parkinson’s patients compared to healthy individuals.
• Lower mitochondrial DNA copy numbers correlated with increased Parkinson’s risk, more severe motor symptoms, reduced daily activity, and diminished sense of smell, but showed no consistent association with cognitive performance.
• After adjusting for blood cell counts, particularly neutrophils and lymphocytes, the connection between mitochondrial DNA copy numbers and Parkinson’s risk/severity weakened significantly.
• Genetic analysis using bidirectional Mendelian randomization found no direct causal link between lower mitochondrial DNA copy numbers and Parkinson’s disease.
• The findings suggest blood mitochondrial DNA copy numbers may serve as markers of immune response rather than mitochondrial dysfunction, prompting new directions for diagnostic development.

“The ultimate goal is to be able to screen for Parkinson’s disease in a similar way to the national screening program for bowel cancer, so people can get access to medication sooner.”
– Melanie Bahlo, PhD, researcher at the WEHI and the study’s lead author

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