A team of biologists from the Russian Academy of Sciences have developed a new way to measure the level of the stress hormone cortisol without using a blood test, by measuring its concentration in hair, according to an article published in the journal Metabolic Brain Disease.
Regina Konstantinova — In recent years researchers have started to pay more attention to stress and how it affects the brain and the body.
According to the team’s hypothesis, the development of depressive disorders is closely associated with the patient’s inability to adequately respond to stress.
The main indicator of stress is cortisol; its levels rise as stress increases. Usually the cortisol test is conducted on a blood sample; however, this approach is not always convenient.
“The level of cortisol measured from the blood gives us the ‘here-and-now’ level and, moreover, it is also very dependent on the time of day,” Professor Natalia Gulyaeva, Deputy Director and the Head of the Laboratory of Functional Biochemistry of the Nervous System in the Institute of Higher Nervous Activity and Neurophysiology, RAS, who leads the research.
In addition, for some men and women the blood sampling process may be stressful on its own and increase the level of hormone, exaggerating the real level.
“As for the hair cortisol, it shows the level of the previously accumulated hormone. In other words, this figure represents the average cortisol level — in the hair, this hormone accumulates in proportion to its release into the blood and distribution in the body. We know that in a month hair grow about 1 cm long; thus analyzing 1 cm of a hair from the root, we know the whole ‘gained’ amount of cortisol in the past month,” Prof. Gulyaeva explained.
Using this approach, Gulyaeva and her colleagues measured the levels of stress of 20 women suffering from severe forms of depression, and 20 other participants who did not have any symptoms of depression.
The women with a depressive disorder had hair cortisol levels significantly lower than healthy women of the same age. The higher was the severity of the depression, the lower the level of the “stress hormone” in the hair.
“Cortisol stimulates the recovery processes after stress.
When a large excess of cortisol accumulates, it means the body had excessive stress load.
But if the accumulated amount is substantially less than it should be, it means this important system is exhausted, and the ‘repair mechanism’ after stress doesn’t work at its full.
Thus, the effect of particular stress on the health is even stronger,” the biologist revealed.
Depression is the second most common of all diseases, according to the WHO, and is predicted to take the first place in 10 years, said the leading researcher.
“Women are more likely to suffer from depression than men. Today, it is already the most common disease among female patients. However, our further work will include studying the stress levels of male patients and identification of gender differences as well,” Prof. Gulyaeva said.
The new method is undoubtedly important for developing a better understanding of how to effectively treat depression and possibly prevent it.
“Our approach allows knowing for certain that the patient’s reaction to stress is inadequate and that it’s harder for him to cope with everyday stress than for a healthy person. On the one hand, it allows us to understand one of the most important pathogenetic mechanisms of disease development. On the other hand, in the course of treatment, which is very long, our approach makes it possible to monitor the effectiveness of the treatment once every few months,” the professor concluded.