A number of physical illnesses is caused by the body’s inability to cope with chronic stress conditions. A continuous stimulation of the immune system leads to resource depletion and thus diseases such as hypertension or heart attack. An early detection of chronic stress is extremely problematic, due to a lack of a typical biomarker. It turns out that hair analysis may solve more problems than originally expected.

Stress is a phenomenon leading to a destruction of homeostasis, caused by a physical or psychological stressor. Stress may cause mobilization (called eustress) or be completely negative (distress). The body is able to cope with these stressors until the phase of exhaustion, in which it cannot longer endure the continuous stimulation, consequently leading to illness or even death. Chronic stress biomarker would enable earlier detectionof this condition, therefore minimize its negative effects.

Acute stress has been studied for years on the basis of catecholamines level assessment in plasma, saliva and urine. Cortisol, an adrenal steroid hormone is considered to be a stress hormone just like adrenalin. It works to mobilize the body, increasing blood glucose levels in stressful situations. It can be detected by means of various tests, such as ELISA, LC-MS/MS chromatography or radioimmunoassay (RIAs). Analysis of cortisol levels in blood or saliva samples is effective when it comes to acute stress estimation (it measures the level of stress hormone at the time of sample collection). Finding a biomarker of chronic stress seems to be more problematic, due to its complex etiology, variability, and an extremely long period of collecting the research material.

Collecting saliva samples throughout the day is difficult and unreliable, because of cortisol diurnal fluctuations, and it appears to have a high interindividual variability. Blood tests can give information about the level of free cortisol (active), but also the one bound by plasma proteins. Therefore, the level can be altered when the patient uses hormonal contraception or is pregnant (which leads to an increase in cortisol-binding protein amount, thereby increasing the overall level of cortisol in blood). Sampling with the use of a needle is a stressor itself and may lead to inadequate results. On the other hand urine collection 24h/day is impossible in patients with chronic renal failure and those undergoing dialysis.

So far hair analysis has been used in the monitoring of substances of external origin for instance drugs, heavy metals, etc. So why shouldn’t it be used for substances of endogenous origin as well? Human hair grows approximately 1 centimeter per month – this fact can be used to analyze the levels of stress hormones in a given point of time. Researchers look at the possibilities with a growing fascination. The first attempt to detect cortisol in the fur of laboratory rodents was a success in 2002. The substance was extracted with the use of methanol and further analyzed with ELISA. Glucocorticoids can also be detected with the use of chromatography with a previous incubation in Sorenson buffer. Surprisingly the level of inactive cortisone is way higher than the level of cortisol. It can be attributed to the presence of 11-beta-hydroxysteroid dehydrogenase type II, which converts cortisol to inactive cortisone and is widely present in the hair bulb.

Assuming that the hair grows 1cm per month, the level of cortisol can be measured for a specific period of time. Taking a sample of 1cm from the scalp gives the possibility to analyze the level of stress over the past 30 days. Analysis of the entire length of the hair can help to determine the starting level of coritsol and its level after the stressor appeared. Sampling is completely atraumatic, so the cortisol levels do not increase during the same procedure. Cortisol in the hair structure is stable at room temperature, requires no special storage conditions nor immediate analysis. The sample presents cortisol level in recent months or even years, allowing a long term analysis of the issue, while the material obtained from saliva or plasma provides information about the level of stress hormone only in the exact moment of sampling.

A rapid detection of chronic stress may prevent its further consequences. Patients can be provided with a fast change of environment, relaxation or pharmacological treatment. This excellent retrospective method can also be used to monitor hormone replacement therapy in patients with adrenal deficiency. Hair analysis gains increasing popularity and respect in scientific circles.

Written by: Maria Bilińska

Source:
1. Hair cortisol as a biological marker of chronic stress: Current status, future directions and unanswered questions Psychoneuroendocrinology Volume: 37, Issue: 5, May, 2012, pp. 589-601 Russell, Evan; Koren, Gideon; Rieder, Michael;
2. Evaluation of a method to measure long term cortisol levels Steroids Volume: 76, Issue: 10-11, September – October, 2011, pp. 1032-1036 Manenschijn, Laura; Koper, Jan W.; Lamberts, Steven W.J.; van Rossum, Elisabeth F.C. 3. An assessment of cortisol analysis in hair and its clinical applications Forensic Science International Volume: 196, Issue: 1-3, March 20, 2010, pp. 32-37 Gow, R.; Thomson, S.; Rieder, M.; Van Uum, S.; Koren, G.

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