Long before the appearance of motor symptoms.
Parkinson is the second most frequent neurodegenerative disease in France, with nearly 200,000 people affected. The main symptoms are tremors, stiff muscles and slowness of movements … This disease is characterized by the progressive destruction of neurons that produce dopamine, a chemical messenger essential to the control of gestures. Until now, research has thought that the brain was the first organ affected by the disease. However, a recent American-Chinese study suggests that another organ could, in reality, be the very first affected by the disease.
To carry out their work, the researchers have analyzed tissue samples from two groups of patients: the first suffering from Parkinson’s disease, the latter suffering from a dysfunction of this specific organ, without any known neurological disorder. Their objective: to identify the presence of α-synuclein, a protein which, when it accumulates, forms toxic clusters capable of destroying neurons. Scientists then injected these abnormal proteins into this same organ into healthy mice. Little by little, animals have developed symptoms characteristic of the disease, suggesting that this accumulation could well trigger the pathological process … outside the brain.
This key organ, according to the results published in Nature Neuroscience, is the kidney. Researchers have observed that healthy kidneys effectively filter excess α-synuclein present in the blood. But when their function is altered, this protein eliminates badly. It then accumulates in the renal fabric in the form of toxic clusters, then goes back to the brain by borrowing the nerves, like an invisible highway. “This suggests that the kidney is not just collateral damage, it could be the source”explains Zhentao Zhang, the main author of the study. “Chronic kidney failure could increase the risk of Parkinson’s disease.”
If this hypothesis is confirmed, it could transform our approach to the disease. Because if the accumulation of α-synuclein can be detected in the kidneys before the appearance of motor disorders, this would open the way to much earlier screening. “This study is a powerful reminder that neurodegenerative diseases can have roots beyond the brain.” Taking care of kidney health could thus become a key gesture to prevent Parkinson’s disease.
