Modeling lipid layers of atopic skin and observation of changes in lipid layer properties with changes in ceramide content.

BACKGROUND: Studies have shown that there is a high correlation between atopic dermatitis and decrease in ceramide content in the lipid bilayer of skin. Moreover, it has been shown that the reduction in ceramide content in the stratum corneum is unique to atopic dermatitis, indicating that there are particular structural differences between the lipid bilayers of normal and atopic skin. AIM: This study aimed to compare the lipid bilayer of the atopic skin with that of the healthy skin and to establish a structural model of the lipid bilayer for atopy. METHODS: Molecular dynamics simulations were performed using NAMD 2.8. Models of lipid bilayers of normal skin and atopic skin, and a model of lipid bilayer containing only ceramide were built with CHARMM-GUI. The thickness, area occupied per lipid, and alignment of lipids were compared among the three models. Potential mean force (PMF) of the sodium laureth sulfate (SLES) on lipid bilayers was calculated to predict the affinity between SLES and lipid bilayers. RESULTS: Potential mean force calculations showed that the lipid bilayer of atopic skin was able to absorb the surfactant more easily than that of normal skin. CONCLUSIONS: When the ceramide ratio is low, the thickness of lipid bilayer is reduced and its structure is weakened. Other structural differences between the lipid layers of normal and atopic skin included increased area per lipid and poor alignment of lipids. Further, the atopy lipid bilayer model was found to absorb more SLES than the normal skin lipid bilayer model.

Analysis of the Maillard reaction in human hair using Fourier transform infrared spectroscopic imaging and a focal-plane array detector.

The Maillard reaction has been well researched and used in the food industry and the fields of environmental science and organic chemistry. Here, we induced the Maillard reaction inside human hair and analyzed its effects by using Fourier transform infrared spectroscopy with a focal-plane array (FTIR-FPA) detector. We used arginine (A), glycine (G), and D-xylose (X) to generate the Maillard reaction by dissolving them in purified water and heating it to 150 °C. This label-free process generated a complex compound (named AGX after its ingredients) with a monomer structure, which was determined by using nuclear magnetic resonance (NMR) and FTIR-FPA. This compound was stable in hair and substantially increased its tensile strength. To our knowledge, we are the first to report the formation of this monomer in human hair, and our study provides insights into a new method that could be used to improve the condition of damaged or aging hair.

The inhibitory effect of Scutellaria baicalensis extract and its active compound, baicalin, on the translocation of the androgen receptor with implications for preventing androgenetic alopecia.

Androgens affect several human skin and prostate functions, and the androgen receptor is crucial for regulating the androgen-related mechanisms. In this study, we assessed the antagonizing effects of a Scutellaria baicalensis extract and its main component baicalin on proliferation of human scalp dermal papilla cells. First, the extract and baicalin slightly dissociated the radioisotope-labeled androgen receptor-agonist complex in the androgen receptor binding assay, and the IC50 values were measured to assess the androgen receptor antagonistic effect of the extract (93 µg/mL) and baicalin (54.1 µM). Second, the extract and baicalin treatments dose-dependently inhibited the overgrowth of LNCaP prostate cancer cells, which were stimulated by dihydrotestosterone. Third, the extract and baicalin inhibited nuclear translocation of the androgen receptor stimulated by dihydrotestosterone in human dermal papilla cells. Additionally, the extract and baicalin enhanced proliferation of human dermal papilla cells in vitro. These results show that the extract and baicalin inhibited androgen activation signaling and promoted hDPC proliferation, suggesting that they could be used as active ingredients for treating androgen-associated disorders, such as androgenetic alopecia.