The University of Navarra researcher Mercedes Erburu has defended a doctoral thesis about the influence of environmental factors on Genetics (epigenetics) in depressive disorders, which, according to her, affect 15% of people living in Navarra.

Like other neuropsychiatric disorders, depression is the result of the interaction between genetic, psychosocial and environmental subject factors. "This fact, as well as the limitations of postmortem brain and neuroimaging study techniques, has made it difficult to understand how the molecules involved in the development of the disease act," he explains.

However, epigenetic factors have recently been suggested as risk indicators for the disease, which would explain the enormous variability among individuals who suffer from it and the difference in response to treatments," explains the doctor from department of Pharmacy and Toxicology.

Precisely, the research developed by Mercedes Erburu has focused on the role of two epigenetic proteins, HDAC5 and SIRT2, associated with depression and the beneficial action of antidepressants.

As the new doctor has been able to confirm, chronic stress causes an increase in the HDAC5 protein in the cells of the prefrontal cortex of the brain in mice in which the disease has been induced. "In animal models, this protein promotes DNA condensation in cells and limits the synthesis of some genes, which contributes to the depressive state. In addition, we have found that antidepressants, by raising serotonin and noradrenaline levels, counteract this effect," explains the scientist.

Likewise, his work has shown that there is an increase of SIRT2 proteins in the prefrontal cortex of post-mortem depressed patients and in a model of depression in mice. "These works allowed us to see that chronic treatment with antidepressants markedly reduces this protein in the animal model , although more complete programs of study in patients is necessary", he concludes.

60,000 deaths per year in the EU

As the scientist from Navarra points out, this disease "is the most common affective disorder and, according to the World Health Organization (WHO), it is also one of the main causes of disability due to its functional impact, its tendency to become chronic and recurrent, which prevents sufferers from coping with daily life, as it deteriorates the social and labor area of the patients".

"As a consequence," he adds, "it has a major economic impact, both on the healthcare system and on society itself. Today it is known that this ailment is one of the main risk factors for suicide, representing the cause of death of almost 60,000 people a year in the European Union, well above deaths due to traffic accidents."