Alzheimer’s, the most famous dementia

published on Thursday, June 02, 2022 at 5:34 p.m.

Alzheimer’s disease is the most well-known and widespread dementia, with no treatment currently available to cure or prevent it.

She sees the patient irreparably losing his memory and his capacity for judgment, during an evolution which generally takes several years.

At least 30 million people are affected worldwide, according to the World Health Organization (WHO). This figure remains imprecise because it is not easy to distinguish Alzheimer’s disease from other dementias, for example of vascular origin.

Like other dementias, Alzheimer’s disease represents one of the main contemporary public health problems because people with the disease lose their independence, placing an important emotional burden on their loved ones and financially on health systems.

This is all the more the case in countries where the population is the oldest, ie the main developed countries, with the disease declaring itself largely among those over 65 years of age. It also affects women significantly more than men.

Compared to other dementias, the disease, described for the first time by the German doctor Alois Alzheimer at the beginning of the 20th century, is distinguished by its mode of action, which is twofold.

The first of these two phenomena, which are systematically found in Alzheimer’s patients, is the formation of protein plaques, called amyloid, which compress the neurons and ultimately destroy them.

The second comes from another type of protein, called Tau and present in neurons. In patients, they form clumps which also end up causing the death of the affected cells.

But it is not yet clear how these two phenomena are linked. It is also largely unknown what causes their appearance and, even, to what extent they explain the course of the disease. We are thus increasingly calling into question the long-dominant hypothesis that the formation of amyloid plaques is a triggering factor and not the consequence of other mechanisms.

Consequence: despite decades of research, there is currently no treatment that can cure the disease or prevent its onset.

Main advance for 20 years, a treatment of the American laboratory Biogen, which targets amyloid proteins, obtained some results and was approved this year for certain cases by the American authorities. But its effects remain limited and its therapeutic interest is not unanimous.

Another debate concerns the prevention of the disease, since it very rarely has a hereditary component.

Several risk factors – a dozen – are currently listed for all dementias. The most frequent are deafness, a low level of education, smoking, the existence of depression and isolation.

The authors of a reference study dating from 2020 estimate that 40% of dementias could therefore be avoided and delayed by acting on these symptoms. But this figure is disputed by other researchers who consider this reading too simplistic.

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