American researchers have studied the connections between air particles, our sense of smell, and neurological diseases.
Neurodegenerative diseases such as Alzheimer’s or Parkinson’s cause a deterioration in the functioning of nerve cells, in particular neurons. This causes cognitive-behavioural, sensory and motor disorders. Over the years, researchers have begun to link these afflictions to air pollution. In a study published in the journal eLifeAmerican researchers have gone further by studying the connections between air particles, our sense of smell, and neurological diseases.
Researchers at Penn State University were particularly interested in cerebrospinal fluid (CSF), in which the brain and spinal cord bathe. Because the latter cleans the waste around the brain and neurological diseases such as Parkinson’s and Alzheimer’s are characterized by an accumulation of defective or misshapen proteins. Also, the “cleaning” of the LCS could be involved, explain the authors in the preamble to the study.
Less smell, less LCS
Having discovered that the LCS could leak through the nose and knowing that a diminished sense of smell could herald a neurological condition, the researchers destroyed the olfactory sensory nerves (the only part of the LCS in direct contact with the environment outside) of mice with zinc sulphate. Unsurprisingly, this took away their sense of smell and greatly reduced the flow of LCS from their muzzle.
In order to avoid increasing the pressure inside the central nervous system, the cerebral lymphatic system takes over and the body produces less LCS, explain the researchers. Thus, over time, pollution could damage olfactory neurons, modifying the production of LCS. Since the latter is vital for cleaning out the “metabolic trash” of the central nervous system, it could play a role in the development of neurological diseases.
Further research needs to take place
While this study is interesting, the researchers failed to define what exact path the pollution took to impact the brain. “From now on, we would like to collaborate with a laboratory of the Materials Research Institute which works with particles of soot or jet fuel”, they conclude.
Eventually, these discoveries may lead to better treatments for people with Parkinson’s and Alzheimer’s disease, both of which are currently incurable. Today in France, more than 200,000 people are affected by Parkinson’s and 900,000Alzheimer’s. The French population being increasingly old, these figures are also constantly increasing, recalls Inserm.
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