Reconstruction Of Tissue Engineered Skin With Epidermal, Dermal And Adipose Tissue Layers

Tissue engineering is an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function or a whole organ.According to the definition, the tissue engineered skin refers to a combination of skin cells, engineering and materials methods, and suitable biochemical and physio-chemical factors to improve or replace biological functions of skin. It can be classified into 3 categories by its structure, tissue engineered epidermis, tissue engineered dermis and full thickness tissue engineered skin.The application of tissue engineered skin can be divided into 2 parts. For in vivo, it can be applied to skin disease and skin wound; For in vitro, it can be applied to test chemicals in chemistry and cosmetics as skin model. Especially, the application to test corrosive, irritant and phototoxicity is well developed.European Centre for the Validation of Alternative Methods has strong experiences in this field that so far, the tissue engineered skin EpiDerm and EpiSkin have successfully validated for corrosive test, and EpiSkin has successfully validated for irritant test. Both of skin models are tissue engineered skin, which means the skin models contain only epidermal liked structure.However, as we know, anatomically and functionally the skin has 3 layers, epidermal, dermal and adipose tissue layers. Besides, the 3 layers interact with each other. Adipose tissue plays very important function, and so, tissue engineered skin contains either epidermis or dermis is unintact and not optimal.In the present study, we pay our attention to the method of reconstruction of tissue engineered skin with epidermal, dermal and adipose tissue layers. The method contained 2 steps, first, reconstruction of adipose tissue engineering, second, combining the adipose tissue split and skin cells to collagen to reconstruct skin with 3 layers. The results are as following:1. The adipose derived stem cells were isolated and induced into fat cells, and then implanted into nude mice for 6 weeks. The newly formed tissue was analyzed by histology, oil red O and RT-PCR for PPARγ2 and C/EBPα. The adipose tissue engineering was successfully reconstructed.2. After combined the adipose tissue split and skin cells to collagen, and then cultured the combination in special medium, the skin was analyzed by histology, fluorescence microscope, oil red O and RT-PCR for PPARγ2 and C/EBPα. The tissue engineered skin with epidermal, dermal and adipose tissue layers was successfully reconstructed.