Department of Oral Histology and Pathology, School of Stomatology, The Fourth Military Medical University, Xi'an, China.
Cells Tissues Organs. 2012;195(3):197-206. doi: 10.1159/000324921. Epub 2011 Apr 15.
Many studies demonstrate that the type of adjacent mesenchymal cells can affect epidermal morphogenesis of bilayered tissue-engineered skin. However, whether a mixture of different mesenchymal cell types can improve epidermal morphogenesis of bioengineered skin remains unknown. In this study, keratinocytes, dermal fibroblasts and adipose tissue-derived stem cells (ADSCs) were isolated and purified from human skin and subcutaneous fat. Conditioned medium generated from a mixture of dermal fibroblasts and ADSCs at the ratio of 1:1 was superior to that from fibroblasts or ADSCs alone in promoting keratinocyte proliferation, as indicated by MTT assay. Furthermore, ELISA results showed that the cytokine levels of human hepatocyte growth factor and keratinocyte growth factor (also known as FGF7) in the mixed fibroblasts/ADSC group were higher than those in the ADSC or dermal fibroblasts group. To examine the potential roles of mixed fibroblasts and ADSCs on epidermal morphogenesis, a three-dimensional tissue engineered skin system was applied. Histological analyses demonstrated that keratinocytes proliferated extensively over the mixture of fibroblasts and ADSCs, and formed a thick epidermal layer with well-differentiated structures. Keratin 10 (epidermal differentiation marker) was expressed in the suprabasal layer of bilayered tissue-engineered skin in the mixed fibroblasts and ADSCs group. Desmosomes and hemidesmosomes were detected in the newly formed epidermis by transmission electron microscopy analysis. Together, these findings revealed for the first time that a mixture of fibroblasts and ADSCs in bilayered tissue-engineered skin can improve epidermal morphogenesis.
许多研究表明，相邻间充质细胞的类型可以影响双层组织工程皮肤的表皮形态发生。然而，不同类型的间充质细胞混合物是否可以改善生物工程皮肤的表皮形态发生尚不清楚。在这项研究中，从人皮肤和皮下脂肪中分离和纯化了角质形成细胞、真皮成纤维细胞和脂肪组织来源的干细胞（ADSCs）。MTT 测定表明，真皮成纤维细胞和 ADSC 以 1:1 的比例混合产生的条件培养基在促进角质形成细胞增殖方面优于单独的成纤维细胞或 ADSC。此外，ELISA 结果表明，混合成纤维细胞/ADSC 组的人肝细胞生长因子和角质形成细胞生长因子（也称为 FGF7）的细胞因子水平高于 ADSC 或真皮成纤维细胞组。为了研究混合成纤维细胞和 ADSCs 对表皮形态发生的潜在作用，应用了三维组织工程皮肤系统。组织学分析表明，角质形成细胞在成纤维细胞和 ADSC 的混合物上广泛增殖，并形成具有良好分化结构的厚表皮层。角蛋白 10（表皮分化标志物）在混合成纤维细胞和 ADSC 的双层组织工程皮肤的基底层表达。透射电子显微镜分析检测到新形成的表皮中的桥粒和半桥粒。总之，这些发现首次揭示了双层组织工程皮肤中成纤维细胞和 ADSC 的混合物可以改善表皮形态发生。
