Pandemic stress and the role of sustained cortisol exposure in scalp samples promoting inflammatory cytokine dysregulation.
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Presented by: Colin McGuckin
INTRODUCTION: Living with stress came to the forefront of our understanding of sensory science during Pandemic times. Effects of stress on skin have long been discussed, but more research is needed and not enough models are available for proving cosmetic ingredients can help overcome skin stress. Our aim here was both to create a sophisticated analysis model for scalp and prove the effects of cortisol on skin kinetics. Stress and emotions are processed by the brain amygdala which activates the HPA axis of the hypothalamus, anterior pituitary gland and adrenal glands, causing release of the stress hormone cortisol. Feedback loops of cortisol to the hypothalamus and the pituitary can exacerbate the effects and over long periods lead to system-wide effects on not only the brain and emotions, but also the liver, cardiovascular and immune sytems and the skin, the negative effects of which include dermatitis, acne and rashes and can have severe mental health issues for sufferers. COVID-19 being a higher risk factor to the older generation brings even more stress for that age-group and therefore, our study concentrated on an older female cohort.
METHODS: Human scalp samples with hair follicles were collected from local hospitals after elective surgery and full ethical consenting from female donors age range 61 to 71 years. All donors were collected during the Pandemic which was in itself a challenge. Uniform sized ex vivo samples were made and placed into ex vivo culture medium (CTI) to support extended culture. Samples in triplicate were allowed to equilibrate for 24 hours prior to treatment. Donors were split randomly into 2 groups. Group 1 was treated with cortisol for 24 hours and group 2 for 48 hours to mimic longer periods of stress. Cortisol at concentrations of 10, 100 and 500 µM were evaluated with treatment from the lower part of the sample in the media to mimic systemic delivery, with the epidermis at the ‘airlift’ air position. Cell viability was measured with Alamar Blue (resazurin conversion and spectrophotometry) before and after treatments. Anti- and pro- inflammatory effects were investigated by cytokine release (IL-8, IL-1β, IL-6, IL-10, TNF, IL-12p70) using Cytometric Bead Array assay from the supernatant of the medium. Negative control was medium only whilst positive control was SDS application at 3% for 30 minutes before washing samples and medium change.
RESULTS AND DISCUSSION: Differences in tissue viability between 24 and 48 hours were not significant. However, in all cases, SDS treatment radically reduced sample viability. However, so did 500 µM cortisol, whilst in comparison, 10 and 100 µM cortisol did not reduce the viability of the samples statistically from the controls. As normal, IL-6 and IL-8 were constitutively produced in control samples and significantly reduced with SDS application. In most cases IL-6 and IL-8 were also dose-response reduced by cortisol application at both timepoints indicating an effect on cellular turnover. IL-12p70, IL-1β, IL-10, and TNF were produced in low amounts in all samples, with nearly all production of IL-1β being inhibited by SDS/cortisol (albeit low expression). IL-10 inhibition by cortisol required longer treatment of 48 hours, whilst IL-12p70 showed increases due to SDS and cortisol, which is relevant as a strong TH1 stimulating event and reducing TH2 implicated in increasing local inflammatory events. This is an important early stage in the recruitment of inflammatory cells to the site, since IL-12p70 is a potent regulator with a significant role in cellular kinetics. Around 25% of samples already had increased levels of IL-12p70 compared others, potentially indicating existing stress.
CONCLUSION: Without doubt, cortisol, a potentially catabolic tissue damaging hormone, has a significant role to play in scalp tissue stress and dysregulation, which warrants further investigation in the cosmetics and dermatology community.
METHODS: Human scalp samples with hair follicles were collected from local hospitals after elective surgery and full ethical consenting from female donors age range 61 to 71 years. All donors were collected during the Pandemic which was in itself a challenge. Uniform sized ex vivo samples were made and placed into ex vivo culture medium (CTI) to support extended culture. Samples in triplicate were allowed to equilibrate for 24 hours prior to treatment. Donors were split randomly into 2 groups. Group 1 was treated with cortisol for 24 hours and group 2 for 48 hours to mimic longer periods of stress. Cortisol at concentrations of 10, 100 and 500 µM were evaluated with treatment from the lower part of the sample in the media to mimic systemic delivery, with the epidermis at the ‘airlift’ air position. Cell viability was measured with Alamar Blue (resazurin conversion and spectrophotometry) before and after treatments. Anti- and pro- inflammatory effects were investigated by cytokine release (IL-8, IL-1β, IL-6, IL-10, TNF, IL-12p70) using Cytometric Bead Array assay from the supernatant of the medium. Negative control was medium only whilst positive control was SDS application at 3% for 30 minutes before washing samples and medium change.
RESULTS AND DISCUSSION: Differences in tissue viability between 24 and 48 hours were not significant. However, in all cases, SDS treatment radically reduced sample viability. However, so did 500 µM cortisol, whilst in comparison, 10 and 100 µM cortisol did not reduce the viability of the samples statistically from the controls. As normal, IL-6 and IL-8 were constitutively produced in control samples and significantly reduced with SDS application. In most cases IL-6 and IL-8 were also dose-response reduced by cortisol application at both timepoints indicating an effect on cellular turnover. IL-12p70, IL-1β, IL-10, and TNF were produced in low amounts in all samples, with nearly all production of IL-1β being inhibited by SDS/cortisol (albeit low expression). IL-10 inhibition by cortisol required longer treatment of 48 hours, whilst IL-12p70 showed increases due to SDS and cortisol, which is relevant as a strong TH1 stimulating event and reducing TH2 implicated in increasing local inflammatory events. This is an important early stage in the recruitment of inflammatory cells to the site, since IL-12p70 is a potent regulator with a significant role in cellular kinetics. Around 25% of samples already had increased levels of IL-12p70 compared others, potentially indicating existing stress.
CONCLUSION: Without doubt, cortisol, a potentially catabolic tissue damaging hormone, has a significant role to play in scalp tissue stress and dysregulation, which warrants further investigation in the cosmetics and dermatology community.