Study of skin reconstruction by using tissue engineering technique

在再生医学领域，培养的上皮和培养的真皮比其他器官的再生要早得多。上皮组织再生先于其他组织再生的一些原因似乎是，与其他器官和组织相比，上皮组织具有结构上的优势，即二维的，不需要刚性支架，而且解剖结构简单。关于角质形成细胞，已发现体细胞(成体)干细胞存在于毛根中。另一个原因是获取干细胞相对容易。我们已经移植了培养的角质形成细胞来治疗至少500名患者的大型皮肤缺损。再生的上皮细胞必须从培养皿底座上分离出来才能移植。通常用蛋白酶将其与盘基分离，为了嫁接，将分离的片材放置在通过模制成与盘相同的形状而制备的载体上。如果上皮片足够结实，用镊子夹起来是没有问题的，但用镊子直接夹住分离的再生表皮片是不可能的，临床上需要一个载体才能将分离的再生上皮片从培养皿中应用到皮片移植床上。此外，由于再生的上皮细胞缺乏真皮成分，单独的上皮移植不能在有真皮缺陷的区域产生良好的效果。这些事实表明，真皮成分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，旨在通过将某种蛋白质与纤维蛋白支架混合来避免角质形成细胞释放的蛋白酶的影响，并增加纤维蛋白本身的体力(专利正在申请中)。

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).