Effects of Locally Applied Glycerol and Xylitol on the Hydration, Barrier Function and Morphological Parameters of the Skin.

Glycerol and xylitol hydrate the skin and improve its barrier function over a short period. We studied the effects of glycerol and xylitol on the physiological properties and morphology of the skin after longer-term application. Twelve volunteers with dry skin were examined. Three areas on the arms were determined. Area 1 served as untreated control. The vehicle was applied to area 2, while area 3 was treated twice daily with a formulation containing glycerol (5%) and xylitol (5%) for 14 days. Transepidermal water loss (TEWL), hydration and biomechanical properties of the skin were monitored. Biopsies were taken for routine histology and immunohistochemistry for filaggrin and matrix metalloproteinase-1 (MMP-1). The polyols increased the skin hydration and protein quantity of filaggrin, elevated the interdigitation index, decreased the TEWL and improved the biomechanical properties of the skin, but did not change the protein expression of MMP-1. A combination of glycerol and xylitol can be useful additional therapy for dry skin.

Reconstruction of Alar-Perialar Defects with a Combined Subcutaneous and Cutaneous Pedicled Rotation-Advancement Nasolabial Flap.

Aim of the Study: During the reconstruction of alar defects involving the upper lip, reconstructive surgeons face the need for various thicknesses of tissues crucial to preserving the facial sulcus which is important for a cosmetically acceptable result. Our aim was to reconstruct the deep perialar and thinner lateral nasal alar defect in a single step procedure with a suitable flap which is reliable, has appropriate blood supply and provides an esthetically good result. Materials and Methods: Extended alar defect was reconstructed with a combined flap in 10 cases. During the procedure, a subcutaneous pedicle was created and the proximal part of the flap was rotated into the defect as a rotational flap. The procedure and the follow-up have been photo-documented in all cases. Furthermore, the perfusion of the flaps was monitored by means of laser Doppler flowmetry. Postoperative complications were evaluated with a semi-quantitative score and the patients completed a patient satisfaction questionnaire, too. Results: An optimal esthetic result was obtained in all cases after the operation. The lateral nasal alar part of the defect was reconstructed with the thinner proximal part of the flap while the deeper perialar region involving the upper lip was covered with the thicker distal part. The flaps have shown sufficient blood flow after the operation. There was no significant pin cushioning or "trap-door" effect in any case. Mild erythema and edema was found in few cases. The patients were satisfied with the cosmetic result of the intervention. Conclusions: The flap is suitable for the reconstruction of alar defects involving the perialar region. It has the advantage of covering the deeper perialar and the thinner alar defects, whilst eliminating the pin cushioning effect of the conventional subcutaneous island pedicle flaps.

Protective effects of glycerol and xylitol in keratinocytes exposed to hyperosmotic stress.

Purpose: Our goal was to study whether glycerol and xylitol provide protection against osmotic stress in keratinocytes. Methods: The experiments were performed on HaCaT keratinocytes. Hyperosmotic stress was induced by the addition of sorbitol (450, 500 and 600 mOsm). Both polyols were applied at two different concentrations (glycerol: 0.027% and 0.27%, xylitol: 0.045% and 0.45%). Cellular viability and cytotoxicity were assessed, intracellular Ca2+ concentration was measured, and the RNA expression of inflammatory cytokines was determined by means of PCR. Differences among groups were analyzed with one-way ANOVA and Holm-Sidak post-hoc test. When the normality test failed, Kruskal-Wallis one-way analysis of variance on ranks, followed by Dunn's method for pairwise multiple comparison was performed. Results: The higher concentrations of the polyols were effective. Glycerol ameliorated the cellular viability while xylitol prevented the rapid Ca2+ signal. Both polyols suppressed the expression of IL-1α but only glycerol decreased the expression of IL-1ß and NFAT5. Conclusions: Glycerol and xylitol protect keratinocytes against osmotic stress. Despite their similar chemical structure, the effect of these polyols displayed differences. Hence, joint application of glycerol and xylitol may be a useful therapeutic approach for different skin disorders.

Antiirritant properties of polyols and amino acids.

BACKGROUND: Antiirritants are used in cosmetic products to prevent or to treat skin irritations that arise during daily life. Data were published earlier on the efficacy of the best-known humectant, glycerol, in reducing irritation. OBJECTIVE: The aim of the present study was to examine the effects of different polyols (including glycerol, xylitol, and mannitol) and the amino acids taurine and glycine on sodium lauryl sulfate (SLS)-induced skin irritation. METHODS: Healthy adult volunteers were patch-tested with 0.1% SLS in the presence or absence of one or another polyol or amino acid. Skin reactions were evaluated via measurements of transepidermal water loss (TEWL). RESULTS: Glycerol and xylitol significantly suppressed the SLS-induced increase in TEWL, whereas mannitol had no effect on the SLS-induced skin irritation. Taurine also inhibited the SLS-induced increase in TEWL, but glycine was not effective in reducing the SLS-induced irritative response. CONCLUSION: Similar to the action of the well-known antiirritant glycerol, SLS-induced skin irritation is suppressed by xylitol and taurine. These results suggest that these agents might also be effective in preventing irritative dermatitis.