Scientists have found that the first target of Alzheimer's disease is the sense of smell
Last reviewed: 23.04.2024
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Alzheimer's disease primarily damages the olfactory neurons. Researchers from the National Institute of Neurological Diseases and Stroke in Bethesda, USA, proved this in experiments on laboratory mice. Thus, it becomes clear why patients who develop senile dementia, first of all, lose their sense of smell.
"The difficulty in perceiving and distinguishing odors refers to the early symptoms of Alzheimer's," explains Leonardo Belluscio, research supervisor. - And this symptom can serve for early diagnosis of the disease. The changes that occur in the olfactory system are similar to those that occur throughout the brain, but they begin earlier. "
Most experts link the causes of the development of Alzheimer's disease with the beta-amyloid protein, which is deposited in neurons of the brain in the form of plaques, which leads to the degradation and death of nerve cells. New data showed that the pathology leading to the death of neurons develops even before the appearance of plaques proper.
Belluschio and his colleagues worked with genetically altered mice that developed human protein, the beta-amyloid precursor (APP) in its mutant version, in olfactory neurons. In humans, this mutation accompanies the early onset of Alzheimer's disease (up to 65 years), it is shown that the early disease is of a family nature.
At the age of three weeks, mice with a mutant APP killed four times as many olfactory neurons as in control animals. And plaques in these neurons did not arise. This convinced scientists that the death of neurons is not directly related to plaques, but is associated only with the mutant protein. When they lowered its high level in the olfactory neurons, they stopped killing.
This encouraged the researchers: it means they not only confirmed that the olfactory cells take the first stroke, but also showed that the pathological process can be stopped.
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