426 Effect of L-4-thiazolylalanine on skin barrier strength

Skin barrier properties are critical for maintaining epidermal water content, protecting from environmental factors, and providing first line of defense against pathogens. In this study, the effect a non-proteinogenic amino acid, L-4-Thiazolylalanine (L4), on important aspect skin health was evaluated by in vitro vivo biomarkers. 3D human models were treated with 0.3% L4. After 48h, RNA samples collected gene expression analyzed. Significant increase ALOXE3 (protein eLOX-3) vs. vehicle (VEH) (+27%) measured. eLOX-3 is member lipoxygenase family required epidermis covalent linkage ceramides to proteins cornified envelope, an step establishing function. To further evaluate integrity, trans-epithelial electrical resistance (TEER) measured tissues at basal level as well upon disruption. TEER quantitative method that allows strength evaluation. values highly related tight junction function decrease disruption induced calcium depletion. L4 treatment significant protected low calcium-induced decrease. Clinically, 4 weeks had better integrity control. This shown via instrumentation evaluation biomarkers tape stripping. A fluorescence-based assay used quantify enzymatic activity 12R-LOX, another maturation ceramides. 12R-LOX after (+31%) stronger subjects 40 years-old older (+45%). conclusion, led modulation strength, making it desirable ingredient topical treatments.