Application of cell-sheet engineering for reconstitution of functional thyroid tissue from isolated thyroid cells

We have recently used a tissue-engineered cell sheet system with temperature-sensitive culture dishes to regenerate tissues such as corneal epithelial graft sheets, bioartificial tracheas, mucosal epithelial sheets for esophageal ulcers, and pulsatile cardiac tissue grafts, all of which can be used in clinical medicine. With regard to the thyroid gland, the three-dimensional follicular structure consists of polarized thyroid epithelial cells, and this structure is important for the production and secretion of thyroid hormones. In order to regenerate thyroid tissue from isolated cells, we used temperature-responsive culture dishes to harvest thyroid follicular cell sheets in the first step of reconstituting functional thyroid tissue. Initial trials demonstrated that the following conditions improved the recovery of cells sheets: 1) pretreatment of the dishes with serum, 2) use of medium free of thyroid stimulating hormone (TSH), and 3) co-culture with skin fibroblasts.