Use of mesenchymal stem cells in three-dimensional models of the epidermis: applicability in tissue engineering

Abstract

The epidermis is formed by strata or layers composed by cells called keratinocytes, which proliferate in the basal layer and, as they are impelled to the more superficial layers, differentiate and express stratum-specific proteins such as cytokeratins, involucrin and epidermal kallikreins. In certain pathological conditions or trauma of the skin, the dynamics between the processes of keratinocyte proliferation and differentiation are affected, and clinical and surgical approaches are necessary for its reestablishment. Currently, tissue engineering has been important tool for both skin regeneration and the proposition of adjuvants that accelerate the wound healing process. In this context, emerges from umbilical cord mesenchymal stem cells (MSC), whose self-renewal potential, ability to differentiate into several cell types, and hypoimmunogenic properties have increased their use in cell therapy. In addition, the paracrine effects of CTM make them strong candidates in the healing process for epidermal reconstitution. In this sense, this project aims to evaluate the potential of transdifferentiation of the umbilical cord CTM in keratinocytes in three - dimensional models of epidermis in vitro, using different dermal equivalents, as well as to study the expression of factors involved in the healing process in the proposed models. Collagen gels, scaffolds and absorbable pads will be used as dermal equivalents since they mimic dermal architecture. The morphology of the CTM will be analyzed by microscopic techniques, the expression of epidermal markers will be evaluated by Western blotting and immunofluorescence, and the activity of the epidermal kallikreins will be measured on the hydrolysis of specific fluorogenic substrates. In addition, the expression by CTM of proteins involved in the healing process will be evaluated. This model may contribute to the understanding of the molecular mechanisms involved in the differentiation and healing of the epidermis, besides resulting in therapeutic approaches that may be used in tissue engineering. (AU)