Infant Skin Barrier, Structure, and Enzymatic Activity Differ from Those of Adult in an East Asian Cohort

Skin physiology is dynamically changing over the first years of postnatal life; however, ethnic variations are still unclear. The aim of this study was to characterize infant skin barrier function, epidermal structure, and desquamation-related enzymatic activity as compared to that of adult skin in an East Asian population. The skin properties of 52 infants (3-24 months) and 27 adults (20-40 years) were assessed by noninvasive methods at the dorsal forearm and upper inner arm. Transepidermal water loss and skin surface conductance values were higher and more dispersed for infants compared to adults. Infant skin surface pH was slightly lower than adult on the dorsal forearm. The infant SC and viable epidermis were thinner compared to adults with differences that were site-specific. Although the chymotrypsin-like activity for infant skin was comparable to adult level, the caseinolytic specific activity was significantly higher for the infant cohort. These observations indicate a differently controlled pattern of corneocyte desquamation in infants. In conclusion, structural and functional differences exist between infant and adult skin in the East Asian population pointing to dynamic maturation of the epidermal barrier early in life.

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NATURAL COSMETICS IN THE CARE OF YOUNG CHILDREN

PEDIATRIA Journal named after G N SPERANSKY ◽

10.24110/0031-403x-2020-99-6-155-162 ◽

2020 ◽

Vol 99 (6) ◽

pp. 155-162

Author(s):

O.B. Tamrazova ◽

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S.P. Seleznev ◽

A.V. Tamrazova ◽

◽

...

Keyword(s):

Skin Barrier ◽

Structural Features ◽

Transepidermal Water Loss ◽

General Information ◽

Skin Barrier Function ◽

Skin Physiology ◽

Main Emphasis ◽

Antimicrobial Protection ◽

Irritant Dermatitis ◽

Adaptive Shifts

The article provides general information about the skin physiology of newborns and infants. Structural features of the skin and main adaptive shifts in newborns, are described. Тhe child has an increase in the skin barrier function of the skin, which prevents transepidermal water loss; active synthesis of natural moisturizing factor (NMF) components that control skin hydration; shift of pH to acidic environment; normalization of thermoregulatory functions; enhancement of the photoprotective function; immune restructuring for antimicrobial protection; formation of a normal microbiome. The article describes the consequences of improper skin care of a newborn, using the example of diaper dermatitis, irritant dermatitis, prickly heat and vesiculopustulosis. The importance of using specialized children's cosmetics in caring for an infant is assessed. The basic recommendations for the choice of these products are presented, where the main emphasis is on the choice of products consisting of natural ingredients. Giving preference to natural cosmetics, everyone should carefully study the composition of these products and trust the manufacturers who can guarantee safety of care products for the youngest children.

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Intronic LINE-1 insertion in SLCO1B3 as a highly prevalent cause of rotor syndrome in East Asian population

Journal of Human Genetics ◽

10.1038/s10038-021-00967-1 ◽

2021 ◽

Author(s):

Young-gon Kim ◽

Hobin Sung ◽

Ho Seob Shin ◽

Man Jin Kim ◽

Jee-Soo Lee ◽

...

Keyword(s):

East Asian ◽

Asian Population ◽

East Asian Population ◽

Rotor Syndrome

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EGFR inhibitors switch keratinocytes from a proliferative to a differentiative phenotype affecting epidermal development and barrier function

BMC Cancer ◽

10.1186/s12885-020-07685-5 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Nicolas Joly-Tonetti ◽

Thomas Ondet ◽

Mario Monshouwer ◽

Georgios N. Stamatas

Keyword(s):

Growth Factor ◽

Barrier Function ◽

Kinase Inhibitors ◽

Treatment Protocol ◽

Growth Factor Receptor ◽

Skin Barrier ◽

Keratinocyte Differentiation ◽

Skin Barrier Function ◽

Epidermal Keratinocytes ◽

Epidermal Structure

Abstract Background Cutaneous adverse drug reactions (CADR) associated with oncology therapy involve 45–100% of patients receiving kinase inhibitors. Such adverse reactions may include skin inflammation, infection, pruritus and dryness, symptoms that can significantly affect the patient’s quality of life. To prevent severe skin damages dose adjustment or drug discontinuation is often required, interfering with the prescribed oncology treatment protocol. This is particularly the case of Epidermal Growth Factor Receptor inhibitors (EGFRi) targeting carcinomas. Since the EGFR pathway is pivotal for epidermal keratinocytes, it is reasonable to hypothesize that EGFRi also affect these cells and therefore interfere with the epidermal structure formation and skin barrier function. Methods To test this hypothesis, the effects of EGFRi and Vascular Endothelial Growth Factor Receptor inhibitors (VEGFRi) at therapeutically relevant concentrations (3, 10, 30, 100 nM) were assessed on proliferation and differentiation markers of human keratinocytes in a novel 3D micro-epidermis tissue culture model. Results EGFRi directly affect basal keratinocyte growth, leading to tissue size reduction and switching keratinocytes from a proliferative to a differentiative phenotype, as evidenced by decreased Ki67 staining and increased filaggrin, desmoglein-1 and involucrin expression compared to control. These effects lead to skin barrier impairment, which can be observed in a reconstructed human epidermis model showing a decrease in trans-epidermal water loss rates. On the other hand, pan-kinase inhibitors mainly targeting VEGFR barely affect keratinocyte differentiation and rather promote a proliferative phenotype. Conclusions This study contributes to the mechanistic understanding of the clinically observed CADR during therapy with EGFRi. These in vitro results suggest a specific mode of action of EGFRi by directly affecting keratinocyte growth and barrier function.

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