A study in which the Higher Council for Scientific Research ( CSIC ) has participated has shown that a region of the human brain , known as the dentate gyrus , produces new neurons until the ninth decade of life in those people who do not suffer from any neurological disease; while this mechanism, called adult hippocampal neurogenesis, is damaged in patients with Alzheimer's disease.

"Despite a slight reduction in the number of neurons generated during aging , a large number of these neurons are still present in the dentate gyrus of individuals who do not suffer from any neurological disease at least until the age of 87," explains the study coordinator María Llorens-Martín , researcher at the Severo Ochoa Molecular Biology Center (joint center of the CSIC and the Autonomous University of Madrid).

The results , which have been published in the journal 'Nature Medicine', are transcendent because the birth of new neurons in the adult human brain is of great importance for modern medicine , since this special type of neurons generated in the hippocampus participates in the acquisition of new memories and learning in mice.

Contradictory results

Recent results have reopened the debate in this field by not detecting the presence of these cells in the human brain. This work analyzes in depth the causes of obtaining possible contradictory results found by different research groups.

The study also comparatively analyzes the process of adult hippocampal neurogenesis in a group of 13 healthy individuals and 45 patients with Alzheimer's disease . The authors have discovered that the number of new neurons decreases drastically in the initial stages of the disease and continues to decrease progressively as the disease progresses. Furthermore, these cells encounter problems at different stages of the neuron maturation process.

As a consequence of this blockage, the number of neurons generated that finally reaches full maturation is much lower in these patients. "These findings are of great importance in the study of neurodegenerative diseases and specifically in the study of Alzheimer's disease ," he adds.

In this sense, the early detection of a decrease in the generation of new neurons could be an early marker of the disease. On the other hand, he adds, "if it were possible to increase the birth and maturation of new neurons in a similar way to what is done in laboratory mice, new therapeutic possibilities could open up that could be useful to alleviate or slow down the progression of this disease." illness," he says.

This study is the result of the collaboration of researchers from the Autonomous University of Madrid, the CSIC, the Center for Networked Biomedical Research in Neurodegenerative Diseases (Ciberned), the CIEN Foundation and the European University of Madrid.

Investigation Development

The study demonstrates that the chemical treatments to which it is necessary to subject human brain tissue samples for subsequent study critically affect the detection of the presence of immature neurons. The researchers showed that, after subjecting samples obtained from the same subjects to different chemical treatments, very different numbers of cells were observed.

Furthermore, when these treatments were more aggressive or prolonged in time, the signal emitted by the new neurons disappeared completely. «Our work identifies a combination of methods that allows us to visualize the birth of new neurons in the adult human dentate gyrus. This methodology has allowed us to know, for the first time, unique data about the maturation of the new neurons generated in this region of the brain," he points out.

Thus, he continues, "we have been able to study in depth the stages that new neurons go through before fully maturing, what proteins they synthesize, and how they change shape and position within the dentate gyrus. This maturation process shares several characteristics with those described in other mammal species," adds Llorens-Martín.

Article extracted Source: Medical Editorial