Examination of women's skin reveals significant chemical changes in response to psychological stress

Examination of women's skin reveals significant chemical changes in response to psychological stress

In a recent study published in Scientific Reports, researchers examined the volatile organic compounds (VOCs) that skin produces in response to psychological stress.

background

The volatilome is a collection of volatile organic compounds (VOCs) produced by plants, microbes or animals that contribute to the odor profile of the skin and represent part of the odor pressure.

The human volatilome contains thousands of VOCs released from various sources including exhaled air, saliva, blood, urine, milk, feces, and skin emissions.

These VOCs are not only associated with clinical conditions; They can also be exogenous and result from environmental influences or product use. Eccrine, sebaceous and apocrine glands, in conjunction with naturally occurring microorganisms, produce most of the skin's endogenous volatiles.

Psychological stress can disrupt the skin barrier and alter skin inflammatory responses, although its effects on human skin VOC emissions are unclear.

About the study

In the present study, researchers examined the effects of stress on skin VOC emissions.

The main objective was to examine volatile organic compounds secreted from forehead skin after stress induction in middle-aged women by performing cognitive tasks such as problem solving and word encoding to identify VOC stress markers.

The secondary purpose was to investigate the influence of skin sebum concentration, pH and transepidermal water loss (TEWL) on VOC release.

The study included 35 non-smoking women aged 24 to 40 (average age 35). The researchers sampled VOCs from the forehead before and after stress induction with a silicone polymer. They evaluated the linearity of the sampling device using four VOCs: heptanal, 2-phenylethanol, isoamyl acetate, and 2,3-dimethylpyrazine.

Three measurements were performed simultaneously within the linearity range of the calibration curve using a reference solution of 15 ng/µL to evaluate the repeatability of the technique.

The team induced cognitive stress through timed exercises using customized software, including a clock for semantic and arithmetic tasks, and confirmed this using physiological and clinical data.

They assessed stress levels using a State-Trait Anxiety Inventory (STAI) questionnaire, verbal expression analysis, and clinical assessments.

The researchers identified and quantified VOCs using gas chromatography-mass spectrometry (GC-MS). Stress induction was evidenced by significant increases in state anxiety as measured by the questionnaire, by changes in electrodermal activity (EDA) measures, and by literal expressions of stress.

The researchers also examined sebum production and skin pH. They analyzed the data qualitatively and quantitatively to determine VOC expression before and after the psychological stress tests.

The RSD was determined for each volatile chemical using the average relative abundance values ​​for two to three predominant ions.

To examine the durability of adsorbed VOCs on the silicon polymer, researchers conducted assessments on day 3.0 and day 12 after the sampling phase, simulating the delay between invoicing and GC-MS assessment.

They derived three parameters from the EDA signals collected during the adaptation and stress induction phases. The first parameter was the average SCL (µS). The second parameter was the frequency (peaks/minute), while the third was the average amplitude (µS) of the NS-SCRs.

Results

The study found 198 VOCs with higher concentrations of straight-chain alkanes, alcohols, esters, cyclic alkanes, nitrogen compounds and ketones. Of the chemicals, 69 came from cosmetic ingredients, 49 from food, 37 from human or microbial metabolic processes and 33 from the environment.

Three VOCs (2-hydroxyethyl acetate, 3-methylpentadecane, and 2-hydroxyethyl propanoate) were associated with stress induction, and 14 compounds were statistically significant.

The VOCs were mainly from the alkane family, with fatty acyls produced from lipids and ethylbenzenes being the most common. In addition, the researchers characterized a nitrogen molecule (N,N-dibutylformamide).

The least represented molecule was detected at 3.6 ng/µL (2-hydroxyethyl propanoate), while geranylacetone and butylhydroxytoluene were the most common with concentrations of 121 ng/µL and 177 ng/µL, respectively.

The average abundance of primary ions in volatile standards increased dramatically during storage, with RSD values ​​ranging from 1.3 to 3.1% on day 0 and 9.9% on day 3.

The trait anxiety scores and state anxiety values ​​increased significantly between the stress-free phase and the stress phase by 7.90% and 34%, respectively.

During the stress phase, all three EDA measures increased. The SCL increased from 0.5 to 1.9 µS and the NS-SCRs increased from 0.04 peaks per minute to 4.0. 71% of participants' verbatim statements included deception/failure, stress/pressure, and difficulty/complicated.

After stress induction, sebum levels on the forehead increased by 37%, while skin pH decreased by 14%.

Diploma

Overall, the study results highlighted the influence of psychological stress on the modulation of cutaneous VOC emissions. Relative measurement of these chemicals showed a range of production during the stress period.

They are components of lipid metabolism, oxidative stress, air pollution and cosmetic applications. Some were previously known as disease biomarkers, but only one is stress-related. Future studies could investigate the possible effects of modulating these VOC expressions on skin physiology.

Another approach to this research could be to examine their influence on human communication through understanding chemosignaling.

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