Galectin‐7 in the stratum corneum: a biomarker of the skin barrier function

Abstract Objective Skin barrier disruption often occurs in diseased and damaged skin conditions such as atopic dermatitis ( AD ). We focused the galectin‐7 protein (Gal‐7) as a biomarker of skin condition and assessed whether the content of Gal‐7 in stratum corneum (scGal‐7) could be used as an indicator of skin barrier disruption and as an index of local skin symptoms in AD patients. Methods Alteration of Gal‐7 expression levels in keratinocyte and scGal‐7 contents after barrier disruption by sodium dodecyl sulphate were evaluated in vitro and in vivo , respectively. Correlation between scGal‐7 content and transepidermal water loss ( TEWL ) was examined in 126 healthy subjects. We performed single measurements of scGal‐7 contents in 34 AD patients and serial measurements of 15 inpatients among them. SC samples were collected by the tape‐stripping method, and scGal‐7 content was determined using enzyme‐linked immunosorbent assay. Results Gal‐7 expression in keratinocytes increased after barrier disruption. The scGal‐7 content reflected the disruption of the skin barrier. The scGal‐7 contents and TEWL values correlated in healthy subjects. The scGal‐7 level was higher in AD patients than in healthy subjects. The scGal‐7 contents in the cheek and neck of AD patients significantly correlated with the total and local skin lesion severity scores. Serial measurements in the inpatients showed that the scGal‐7 contents in the cheek and neck decreased in tandem with local severity scores in response to treatment. Conclusion Measurement of scGal‐7 content in tape‐stripped samples was useful for the evaluation of the skin barrier function in dry skin conditions such as AD .