Skin microbiota as a therapeutic target for psoriasis treatment: Trends and perspectives.

Psoriasis is a chronic, immune-mediated disease that has a major negative impact on a patient's quality of life. Although several literature reviews indicate that skin microbiota may play an important role in the development and regulation of the immune and inflammatory response of psoriasis, few clinical studies are demonstrating the benefits of using pre-, pro- and synbiotics as a therapeutic alternative at the management of the disease. In this review, we showed the use of probiotic microorganisms that may contribute to skin homeostasis and compiled the clinical trials that demonstrate the effect of therapy with probiotics on patients with psoriasis, an important area for scientific exploration in dermatology and being the first review article to compile this information.

Rheological Characterization and Safety Evaluation of Non-Ionic Lamellar Liquid Crystalline Systems Containing Retinyl Palmitate.

Retinyl palmitate (RP) is widely used as a special interest ingredient in dermatological formulations to improve the elasticity of the skin and to reduce wrinkles by stimulating collagen synthesis. Nanotechnology-based drug delivery systems, such as liquid crystalline systems (LCSs), can modulate drug permeation into skin and improve the drug action. The effects of such systems on the skin, however, are not completely known. Possible undesirable effects of these formulations on the skin can be detected and interpreted by histopathology and histomorphometry. The objective of this study was to perform a rheological characterization to evaluate the safety of RP used in a lamellar LCS in vitro and in vivo. LCSs containing polyether functional siloxane as a surfactant, silicon glycol copolymer as an oil phase and water at ratios of 60:10:30 and 40:30:30, with (F1v and F2v, respectively) and without (F1 and F2 respectively) RP, were investigated. The rheological characterization was performed using steady shear rate sweep tests and dynamic frequency sweep tests carried out for up to 30 days for various storage temperature conditions (25 ± 2 °C, 37 ± 2 °C and 5 ± 2 °C). Cytotoxic effects were evaluated using J-774 mouse macrophages as a cellular model system. The in vivo tests were conducted on rabbits that had areas of skin treated as follows for 15 days: C (Control); F1; F1v; F2; and F2v. Histomorphometric and histopathological techniques were used to estimate the thicknesses of the epidermis and stratum corneum and the numbers of fibroblasts and leukocytes in the papillary dermis. Mean values were compared by ANOVA, followed by the Tukey test (p < 0.05). The steady shear rate sweep and dynamic frequency sweep tests confirmed the high viscosity of the LCS and the typical pseudo-plastic characteristic of the lamellar system. The RP-unloaded LCS and the RP-loaded LCS did not produce cytotoxicity, nor did they provoke significant thickening of the epidermis and stratum corneum. The number of leukocytes in the treated areas did not change; however, the number of fibroblasts in the area treated with F1v was higher than in the areas treated with the control and F2. The histological analyses demonstrated that none of the formulations irritated the skin and that formulation F1v significantly increased the number of fibroblasts in the dermis, which could result in an increase in the production of collagen.

Skin Delivery and in Vitro Biological Evaluation of Trans-Resveratrol-Loaded Solid Lipid Nanoparticles for Skin Disorder Therapies.

The aim of this study was to evaluate the skin delivery and in vitro biological activity of trans-resveratrol (RES)-loaded solid lipid nanoparticles (SLNs). The SLNs were composed of stearic acid, poloxamer 407, soy phosphatidylcholine (SPC), an aqueous phase and 0.1% RES. The particle size, polydispersity index (PdI) and zeta potential were analyzed by dynamic light scattering (DLS). The SLNs were analyzed by scanning electron microscopy (SEM-FEG) and differential scanning calorimetry (DSC). In vitro RES-SLN skin permeation/retention assays were conducted, and their tyrosinase inhibitory activity was evaluated. An MTT reduction assay was performed on HaCat keratinocytes to determine in vitro cytotoxicity. The formulations had average diameter lower than 200 nm, the addition of SPC promoted increases in PdI in the RES-SLNs, but decreases PdI in the RES-free SLNs and the formulations exhibited zeta potentials smaller than -3 mV. The DSC analysis of the SLNs showed no endothermic peak attributable to RES. Microscopic analysis suggests that the materials formed had nanometric size distribution. Up to 45% of the RES permeated through the skin after 24 h. The RES-loaded SLNs were more effective than kojic acid at inhibiting tyrosinase and proved to be non-toxic in HaCat keratinocytes. The results suggest that the investigated RES-loaded SLNs have potential use in skin disorder therapies.