Introduction: In skin traumas, such as burns, epidermal homeostasis is affected, often requiring clinical approaches. Different therapeutic strategies can be used including transplantation, besides the use of synthetic or natural materials with allogeneic cells. In this context, tissue engineering is an essential tool for skin regeneration, and using mesenchymal stem cells (MSC) from the umbilical cord appears to be a promising strategy in regenerative medicine due to its renewal and differentiation potential and hypo immunogenicity. We evaluated the transdifferentiation of MSC from umbilical cord into keratinocytes in three-dimensional (3D) in vitro skin models, using dermal equivalents composed by type I collagen with dermal fibroblasts and a commercial porcine skin decellularized matrix, both cultured at air-liquid interface (ALI).Methods: The expression of epidermal proteins cytokeratins (CK) 5, 14 and 10, involucrin and filaggrin was investigated by real-time PCR and immunofluorescence, in addition to the activity of epidermal kallikreins (KLK) on the hydrolysis of fluorogenic substrates.Results and discussion: The cultivation of MSCs with differentiation medium on these dermal supports resulted in organotypic cultures characterized by the expression of the epidermal markers CK5, CK14, CK10 and involucrin, mainly on the 7th day of culture, and filaggrin at 10th day in ALI. Also, there was a 3-fold increase in the KLK activity in the epidermal equivalents composed by MSC induced to differentiate into keratinocytes compared to the control (MSC cultivated in the proliferation medium). Specifically, the use of collagen and fibroblasts resulted in a more organized MSC-based organotypic culture in comparison to the decellularized matrix. Despite the non-typical epithelium structure formed by MSC onto dermal equivalents, the expression of important epidermal markers in addition to the paracrine effects of these cells in skin may indicate its potential use to produce skin-based substitutes.

Introduction: Type 2 diabetes mellitus (T2DM) is frequently associated with dyslipidemia, which corresponds to the increase in the triglycerides and fatty acid concentrations in tissues, such as the skeletal muscle. The use of herbal medicines as Uncaria tomentosa (Ut) has been proposed as an auxiliary treatment for patients with T2DM. In this study, it was evaluated the Ut aqueous extract effect on cell viability of skeletal myoblasts from C2C12 lineage exposed to the free fatty acid palmitate (PA), and on the reactive oxygen species (ROS) production, which consists a central event involved in T2DM pathogenesis. Methods: Cells were cultured in Dulbecco's modified Eagle's medium (DMEM), supplemented with 10% fetal bovine serum (FBS), at 37°C humidified atmosphere and 5% CO2. The cells were incubated with PA in different concentrations, in the presence or absence of 250 μg/ml Ut aqueous extract, for 2, 6 or 24 h. After these periods, oxidative stress was evaluated by fluorescence spectroscopy. Results: Incubation of cells with PA and Ut aqueous extract resulted in an increase of, at least, 50% in cell viability compared to control with only PA. The treatment of cells with Ut aqueous extract, for 6 h, followed by exposure to 500 μM PA, caused 38% less ROS formation than those incubated with only the free fatty acid. Conclusion: The Ut aqueous extract promoted a rise in cell viability, reduced cell death and attenuated ROS formation in cultures incubated with 500 μM PA, protecting cells from the fatty acid lipotoxicity.