Differences between Cheeks and Dorsal Hands Skin Properties during Skiing in a Cold and Windy Environment

Background/Purpose: The skin protects against external factors and this skin function can be affected by environmental conditions, including low temperature, low humidity, and high altitude. Therefore, it is important to study the relationship between the environment and the skin. The purpose of this study is to determine how the skin barrier functions change at low temperatures. Methods: This study was performed at a Korean ski resort on January 2015 and evaluated 10 subjects skin condition during skiing. Skin properties were examined at 2 sites (cheeks and dorsal hands) and four time points (indoor;baseline, outdoor;after first skiing and after second skiing, indoor;after taking a shower). Results: The skin hydration on the cheek decreased after the second skiing session and the erythema decreased only after the first skiing while this value on dorsal hand was not changed by skiing. The brightness and yellowness of cheek skin increased and redness decreased therefore, skin color became pale during skiing. The extensibility of cheeks and dorsal hands decreased after skiing. We found positive correlation between skin temperature and redness (r2 = 0.707, p Conclusions: Low temperatures can affect human skin color so that the skin color becomes pale because capillary blood vessels shrink when skin is exposed to cold environment. The cheek skin tends to change easily than dorsal hand during ambient temperature change.

Effects of laminar shear stress versus resveratrol on the citrulline-NO cycle in endothelial cells

Laminar shear stress (LSS) due to pulsatile blood flow enhances endothelial function by multiple mechanisms including NO production. Red wine and its constituent, resveratrol, have also been postulated to provide vascular protective effects. The aim of the present study was to compare the effects of mechanical LSS and pharmacological resveratrol treatments on the endothelial citrulline-NO cycle. Human umbilical vein endothelial cells (HUVECs) were treated with LSS (12 dyn·cm-2) or resveratrol (25 - 100 μM). The expressions of argininosuccinate synthetase 1 (ASS1), argininosuccinate lyase (ASL), nitric oxide synthase 3 (NOS3) and cationic amino acid transporter 1 (CAT1), and the production of NO were determined. The expressions of Kruppel-like factor (KLF) 2 and KLF4 as upstream regulators of ASS1 and NOS3 were also analyzed. LSS strongly increased the mRNA levels of ASS1 (8.3 fold) and NOS3 (5.4 fold) without significant effects on ASL and CAT1 mRNAs. Resveratrol increased the ASS1 mRNA level in a dose-dependent manner up to 3.8 fold at 100 μM. The effects of resveratrol on the expressions of KLF2 and KLF4 mRNAs were smaller than those of LSS. Protein levels of ASS1 and NOS3, and NO production were markedly increased by LSS but resveratrol (50 μM) increased only ASS1 protein level. The results of the current study showed that LSS had greater effects on the citrulline-NO cycle activity leading to NO production, compared to resveratrol. Because resveratrol was not so effective at stimulating the endothelial citrulline-NO cycle, further studies are needed to find more potent drugs that increase the expression of ASS1 and NOS3 genes.