The following abstracts are for recently published research papers that are of interest to the cosmetics industry.
These include papers on an easy-to-use LED device to stimulate hair growth; S. aureus' role in atopic dermatitis pathogenesis; the significant drop in percentage of unprotected skin under 'double application' of sunscreen; and autophagy's potentially reparative role in human dermal fibroblasts stressed with particulate matter.
Trichogenic photostimulation using monolithic flexible vertical ALGAINP light-emitting diodes
Authors: Han EL, Seung HL, Minju J, Jung HS, Yuri A, Daesoo K, Sang HO, Seok HY, Keon JL
Published: 20 August 2018. ACS Nano. DOI: 10.1021/acsnano.8b05568
In today's society alopecia is considered an aesthetic, psychological and social issue.
Although laser-induced skin stimulation is utilised for depilation treatment, such treatment has significant drawbacks, including high energy consumption, large equipment size and limited usage in daily life.
This study presents a wearable photostimulator for hair growth applications using high performance flexible red vertical light-emitting diodes (f-VLEDs).
Flexible micro-scale LEDs were effectively fabricated by a simple monolithic fabrication process, resulting in high light output (∼30mW mm–2), low forward voltage (∼2.8V) and excellent flexibility for wearable bio-stimulation.
Finally, trichogenic stimulation of a hairless mouse was achieved using high-performance red f-VLEDs with high thermal stability, device uniformity and mechanical durability.
The prevalence of antibody responses against staphylococcus aureus antigens in patients with atopic dermatitis: A systematic review and meta-analysis
Authors: de Wit J, Totté JEE, van Buchem FJM, Pasmans SGMA
Published: June 2018. Br J Dermatol. 178(6):1,263-1,271
Staphylococcus aureus plays a role in the pathogenesis of atopic dermatitis (AD), possibly via the expression of various virulence antigens.
An altered antibody response towards these antigens might contribute to inflammation.
This study's objective was to provide an overview of the varying prevalences and odds of antibody responses against S. aureus antigens in patients with AD.
Data were systematically obtained from Embase, MEDLINE, Web of Science, Scopus, Cochrane, PubMed and Google Scholar up to 12 February 2016.
The authors selected all original observational and experimental studies assessing antistaphylococcal antibodies in serum of patients with AD.
Prevalences and odds ratios (ORs) of IgE, IgG, IgM and IgA against S. aureus in patients with AD versus healthy controls were pooled using the random-effects model.
I2 statistics were calculated to assess heterogeneity, and study quality was rated using the Newcastle-Ottawa Scale. Twenty-six articles (2,369 patients) were included, of which ten were controlled studies.
Study quality was fair to poor. Patients with AD had higher prevalences of IgE against staphylococcal enterotoxin (SE)A (OR 8·37, 95% confidence interval 2·93-23·92) and SEB (OR 9·34, 95% confidence interval ·54-24·93) compared with controls. Prevalences of antistaphylococcal IgE were 33% for SEA, 35% for SEB and 16% for toxic shock syndrome toxin-1.
However, the authors note that study heterogeneity and imprecision should be taken into consideration when interpreting the results. Data on IgG, IgM and IgA, as well as other antigens, are limited.
The study concluded that patients with AD more often show an IgE antibody response directed against S. aureus superantigens than healthy controls, supporting a role for S. aureus in AD pathogenesis.
More than 3million people die annually from air pollution, which places air pollution as the world's largest single environmental health risk factor
Sunscreen use optimised by two consecutive applications
Authors: Heerfordt IM, Torsnes LR, Philipsen PA, Wulf HC
Published: 28 March. https://doi.org/10.1371/journal.pone.0193916
Sunscreen users are often inadequately protected and become sunburned.
This study aimed to investigate how much two consecutive sunscreen applications increased the quantity of sunscreen applied and decreased the skin area left without sunscreen (missed area) compared with a single application.
Thirty-one healthy volunteers wearing swimwear were included and applied sunscreen two consecutive times in a laboratory environment.
Participants had pictures taken in black light before and after each application. As sunscreens absorb black light, the darkness of the skin increased with increasing amounts of sunscreen applied.
The authors conducted a standard curve establishing a link between change in picture darkness and quantity of sunscreen.
The quantity of sunscreen at selected skin sites, as well as the percentage of missed area was determined after each application.
Participants had missed a median of 20% of their available body surface after a single application. After double application they had missed 9%.
The decrease in missed areas was significant for the whole body surface and for each of the body regions separately.
The median participant had applied between 13% and 100% more sunscreen at the selected skin sites after double application than after single application.
The authors recommend double application, especially before intense sun exposure.
Air pollution, autophagy, and skin ageing: Impact of particulate matter (PM10) on human dermal fibroblasts
Authors: Park SY, Byun EJ, Lee JD, Kim S, Kim HS
Published: 12 September 2018. Int J Mol Sci. 19(9):2,727
A World Health Organization (WHO) report from 2016 states that more than 3 million people die annually from air pollution, which places air pollution as the world's largest single environmental health risk factor.
Particulate matter (PM) is one of the main components of air pollution, and there is increasing evidence that PM exposure exerts negative effects on the human skin.
To see the impact of air pollution on skin ageing, the study's authors analysed the effect of PM exposure on human dermal fibroblasts (HDFs) with Western blot, enzyme-linked immunosorbent assay (ELISA) and gene analysis.
Cultured HDFs were exposed to PM10 at a concentration of 30μg/cm2 for 24 hours and their gene/protein expression of inflammatory cytokines, fibroblast chemical mediators and autophagy were assessed.
A total of 1,977 genes were found to be differentially expressed following PM exposure. We observed a significantly increased expression of pro-inflammatory genes interleukin (IL)-β, IL-6, IL-8 and IL-33 in dermal fibroblasts exposed to PM10.
Protein expression of IL-6 and IL-8 also significantly increased, which complemented the gene analysis results.
In addition, there was a significant increase in cytochrome P450 (CYP1A1, CYP1B1), matrix metalloproteinase (MMP-1, MMP-3) mRNA expression, and a significant decrease in transforming growth factor (TGF)-β, collagen type I alpha chain (COL1A1, COL1A2) and elastin (ELN) mRNA expression in PM-exposed dermal fibroblasts.
Protein expression of MMP-1 was significantly increased and that of TGF-β and procollagen profoundly decreased, similar to the gene analysis results.
Autophagy, an integrated cellular stress response, was also increased while transmission electron microscopy (TEM) analysis provided evidence of PM internalisation in the autolysosomes.
Taken together, the results demonstrate that PM10 contributes to skin inflammation and skin ageing via impaired collagen synthesis.
Increased autophagy in our study suggests a reparative role of autophagy in HDFs stressed with PM, but its biological significance requires further research.