Study of skin reconstruction by using tissue engineering technique

在再生医学领域，培养的上皮和真皮在很大程度上领先于其他器官的再生。上皮组织的再生之所以先于其他组织的再生，似乎是因为上皮组织与其他器官和组织相比，具有二维结构优势，不需要刚性支架，解剖结构简单。关于角质形成细胞，已经发现在发根中存在体细胞（成体）干细胞。另一个原因是相对容易获得干细胞。我们已经移植了培养的角质形成细胞来治疗至少500名患者的大面积皮肤缺陷。再生的上皮必须从培养皿基部分离出来进行移植。通常用蛋白酶将其与培养皿底座分离，然后将分离的薄片置于与培养皿形状相同的载体上进行嫁接。如果上皮片足够坚固，可以用镊子夹起，则没有问题，但用镊子直接夹起分离的再生表皮片是不可能的，并且在临床中将分离的再生上皮从培养皿中应用到皮肤移植床上需要载体。此外，由于再生上皮缺乏真皮成分，在存在真皮缺陷的区域，仅靠上皮移植不能产生良好的效果。这意味着真皮元素是移植上皮所必需的。为了解决这些问题，我们开发了一种技术，旨在避免角化细胞释放的蛋白酶的影响，并通过将某种蛋白质与纤维蛋白支架混合来增加纤维蛋白本身的物理强度（正在申请专利）。

Cultured epithelium and cultured dermis in particular have considerably preceded regeneration of other organs in the field of regenerative medicine. Some reasons why regeneration of epithelial tissue has preceded regeneration of other tissues seem to be that epithelial tissue has the structural advantages of being two-dimensional and needing no rigid scaffold as well as being anatomically simple as compared to other organs and tissues. With regard to keratinocytes, somatic (adult) stem cells have been found to be present in hair roots. Another reason is that it is relatively easy to harvest the stem cells. We have already transplanted cultured keratinocytes to treat large skin defects in at least 500 patients. The regenerated epithelium must be separated from the dish base for grafting. It is usually separated from the dish base with a proteinase, and for grafting the separated sheet is placed on a carrier prepared by molding in the same shape as the dish. There would be no problem if the epithelium sheet were strong enough to pick up with tweezers, but it is impossible to pick up the separated regenerated epidermis sheet with tweezers directly, and a carrier is required for application of the separated regenerated epithelium from the dish to the skin graft bed in clinical practice. Furthermore, because regenerated epithelium lacks a dermal component, epithelium grafting alone cannot produce good results in areas where there is a dermal defect. The facts mean that dermal elements are required for take of epithelium graft. To solve these problems, we have developed a technique designed to avoid the influence of protease released by keratinocytes and to increase the physical strength of fibrin itself, by mixing a certain protein with fibrin scaffold (Patent pending).