One of the most devastating aspects of aging is the deterioration of report and the appearance of dementia diseases whose frequency increases with age. Among these, Alzheimer's disease has the highest incidence, and requires comprehensive and continuous care that entails very high costs. Alzheimer's disease is an incurable disease that can affect 40% of people over 85 years of age. According to data of the Spanish Confederation of Associations of Relatives of People with Alzheimer's Disease (CEAFA), 800,000 people in Spain currently suffer from the disease. Given the aging of society, this disease is taking on almost epidemic proportions, with the consequent human, social, health, family and economic costs.

To date, moreover, there are no effective treatments available, and although it is an ongoing area research , only symptomatic treatments have been achieved, which delay but do not halt the progression of the disease.
The efforts of clinicians, basic researchers and pharmaceutical companies have made it possible to launch numerous clinical trials. There are currently more than 70 in progress, such as Aducanumab, which has been so highly publicized these days and in whose clinical trials Clínica Universidad de Navarra is also participating. Most of these trials are focused on reducing the levels of beta-amyloid, which is considered the villain in the disease.

However, it does not appear that any of these trials will yield positive results in the short term deadline. Therefore, there is an undeniable need to continue working on the search for new treatments, but also to ask ourselves whether we researchers are adequately choosing the targets on which we are working.

Alzheimer's disease is currently considered to be a multifactorial disease, a consequence of an interaction between susceptibility Genetics and environmental risk factors, such as age, obesity, hypertension, stress or inflammation. These factors, which predispose and increase the risk of developing the disease, are associated with the majority of cases (more than 95%).

Therefore, a lifelong control of risk factors can be core topic to prevent or reduce the number of cases of Alzheimer's disease. According to association Alzheimer's International, the four basic pillars to reduce the risk of developing the disease are: taking care of cardiovascular health, being physically and intellectually active, following a healthy per diem expenses and enjoying social life. Among these factors, stress seems to play a role core topic.

Stress is defined as the physiological reaction of the organism as a defense mechanism to face a status perceived as threatening. In acute episodes, stress is a response to a challenge. But chronic stress situations are associated with serious health risks. Stress is considered to be the epidemic of the 21st century, and can occur both prenatally, as a child - due to childhood abuse, loss or separation from parents, childhood trauma, bullying, etc. - and in adulthood, due to social stress, work stress, and so on. It has been widely described that chronic exhibition to stress can exert harmful effects on brain structure and function, which can manifest immediately after exhibition to stress or as a long-term vulnerability deadline to cognitive and/or neuropsychiatric disorders. Likewise, chronic stressful situations may also accelerate the onset of cognitive impairment in genetically predisposed individuals.

However, the good news is that stress could be a modifiable risk factor, both through programs to reduce and control perceived stress and through medications to control the hormones that mediate stress responses in the body: glucocorticoids. It is pertinent to point out that not all individuals respond in the same way to a stressful status , and that while stressors that appear unexpectedly and unpredictably in daily life are tolerated with great difficulty by many people, others show resilience (they adapt to status). There are already preclinical programs of study showing that these stress-resilient individuals may be resistant to development Alzheimer's disease.

Therefore, if we know the mechanisms of resistance to stress, we may be able to unravel the mechanisms of resistance to Alzheimer's disease.