Brazilian researchers are getting closer to finding ways of treating Alzheimer’s disease, which affects 1 million people in the country and 50 million people worldwide, according to the 2018 World Alzheimer Report. By 2050, that number is expected to triple. The neurodegenerative illness causes dementia, loss of memory and cognitive ability, delusions and mood swings.

Alzheimer’s disease is caused by the accumulation of plaques that cause the death of neurons and the subsequent loss of brain function. Currently, available medication can only ease the symptoms but do not have an effect on the development of the disease itself. That could be about to change with the research conducted by the Federal University of Rio de Janeiro (UFRJ).

One of the key findings of the Brazilian researchers involves a hormone called irisin. According to Sérgio Teixeira Ferreira, a professor of Biophysics, Biochemistry, and Neuroscience and one of the leaders of the research project, irisin is produced by the muscles and its effect has already been studied on other organs. “We have discovered that this hormone is very important for memory formation and its presence is reduced in the brains of Alzheimer’s patients,” he says.

Using mice, the scientists noticed that a lack of irisin has negative effects on memory formation. When the hormone was administered to the animals, their memory was recovered. Irisin is knowingly produced by the muscles, the next step was to verify if exercise could help to increase the amount of the substance in the brain.

The mice underwent a routine of swimming for one hour a day for five weeks. It worked: the concentration of irisin increased, as did the animals’ capacity to learn. Then, to verify that the hormone was actually responsible for the improvements, the mice were genetically altered to become insensitive to irisin. Submitted to the same exercise routine, these rodents were not affected. A similar positive outcome was obtained when administering irisin directly, without exercise.

A drug to reverse Alzheimer’s might be on the horizon

So far, it is safe to say that irisin has a protective effect against Alzheimer’s on the brain, and that physical exercise can increase the levels of the substance. But, according to Mr. Ferreira, this needs further study. Scientists have also not yet discovered exactly how irisin acts to prevent plaque from attacking neurons.

One of the hopes is that the study will be the first step toward developing a drug that can combat—or perhaps reverse—the effects of Alzheimer’s on the brain. Mr. Ferreira warns that it is too early to say if such a medication will come to pass. First of all, he says, it is necessary to know whether there are any side effects of the administration of irisin. In mice, there were none, but a clinical trial is necessary to know if the same applies to humans.

The next steps of the study include understanding how irisin protects the brain. “We need to have a deeper understanding of these mechanisms,” Mr. Teixeira says. But the group lacks resources to go any further. The researcher says that they are not able to carry out clinical trials: “We depend on investments that we do not currently have.”

SocietyJan 11, 2019

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BY Diogo Rodriguez

Rodriguez is a social scientist and journalist based in São Paulo.