BIOMIMETIC TISSUES--ORAL MUCOSACONJUNCTIVA, AND SKIN

口腔皮肤移植是治疗前庭疾病的常用方法。 延长程序，修复创伤引起的缺陷，并 修复因口腔黏膜切除所致的大型口腔粘膜缺损 恶性肿瘤。然而，移植到口腔中的皮肤保持了 它原来的结构和功能，经常让患者体验毛发 从嫁接的皮肤上生长和出汗。理想情况下，口腔粘膜 组织将被用于这种移植物，但这受到缺乏 足够的捐献组织。就像口腔里的组织一样， 结膜是一种覆盖在眼睛和眼皮上的粘膜组织。它 由非角化复层鳞状上皮组成， 与颊粘膜相似。两种情况下产生漫反射 结膜疤痕，导致痛苦的视力丧失：眼 眼表瘢痕性类天疱疮和碱烧伤。那里 目前对这两种情况都没有令人满意的治疗方法。它会 如果口腔粘膜和结膜都能 取而代之的是生物工程替代品。问题是在尝试的时候出现的 为不断更新的组织建立替代物，如 如口腔粘膜和结膜的上皮细胞。所有都是连续的 再生的上皮组织含有干细胞，干细胞是 具有自我更新能力的未分化细胞负责 维持分化的细胞群，这构成了 上皮组织结构。在复层鳞状上皮中，茎 细胞驻留在增殖的基底细胞室中，它有 人们普遍认为，他们分裂的频率比其他人要低 增殖细胞种群的数量，并使它们重新进入 损伤后的上皮细胞。因此，当生物工程时，它是至关重要的 我们包括适当的上皮干细胞的上皮组织 在制造组织的初始阶段。不幸的是，迄今为止， 分离上皮干细胞一直是个问题。以前，使用 氚胸苷，我们能够标记一个亚群的缓慢- 循环小鼠皮肤和口腔粘膜中的基底细胞，我们称之为标记- 保留细胞(LRC)，它显示了干细胞的许多特征 细胞。这种标记方法在过去十年中一直用于 鉴定其他几种上皮细胞中的干细胞，包括四肢 眼睛。最近，我们设计了一种丰富表皮的方法。 干细胞数量从2%增加到50%以上，并进一步 这些选定的细胞显示了生长和再繁殖的潜力 预计将用于表皮干细胞。在这项研究中，我们建议使用我们的 一种从口腔粘膜和口腔粘膜中分离干细胞的新方法 角膜缘上皮细胞，以确定这些细胞显示出克隆性 干细胞的体外特性，并可用于生物工程 用于长期替代的组织，并确定是否有干细胞 细胞维持对内在或外在因素的反应 特定的组织连接。

Grafting skin into the oral cavity is commonly used for vestibular extension procedures, repair of trauma induced defects, and to reconstruct large oral mucosal defects resulting from excision of malignant tumors. However, skin grafted into the oral cavity maintains its original structure and function, and often patients experience hair growth and sweating from the grafted skins. Ideally, oral mucosal tissues would be used for such grafts, but this is limited by a lack of sufficient donor tissue. Like the tissues in the oral cavity, the conjunctiva is a mucosal tissue that lines the eye and the eyelids. It is comprised of a non-keratinizing stratified squamous epithelium, similar to the buccal mucosa. Two conditions produce diffuse conjunctival scarring, which result in painful visual loss: ocular cicatricial pemphigoid and alkali burns of the ocular surface. There is currently no satisfactory treatment for either condition. It would highly desirable if both the oral mucosa and the conjunctiva could be replaced with bioengineered substitutes. The problem arises when trying to build replacements for tissues that are continuously renewing, such as the epithelia of the oral mucosa and conjunctiva. All continuously renewing epithelial tissues contain stem cells, which are the undifferentiated cells capable of self-renewal and responsible for the maintenance of the differentiating cell population, which makes up the epithelial tissue architecture. In stratified squamous epithelia, stem cells reside in the proliferative basal cell compartment, and it has been generally accepted that they divide less frequently than the rest of the proliferative cell population and that they repopulate the epithelia after damage. Thus, it is critical when bioengineering epithelial tissues that we include the appropriate epithelial stem cells in the initial phase of making the tissues. Unfortunately, to date, isolating epithelial stem cells has been problematic. Previously, using tritiated thymidine, we were able to label a subpopulation of slowly- cycling basal cells in mouse skin and oral mucosa that we called label- retaining cells (LRCs), which showed many of the characteristics of stem cells. This tagging method has been used for the last decade to identify stem cells in several other epithelia, including the limbs of the eye. Recently, we have devised a method that enriches the epidermal stem cell population from 2 percent to over 50 percent, and further that these selected cells show the growth and repopulation potential expected for epidermal stem cells. In this study, we propose to use our novel enrichment method to select stem cells from oral mucosal and limbal epithelia, to determine that these cells show the clonogenic properties of stem cells in vitro, and they can be used to bioengineer tissues for use as long term replacements, and to determine whether stem cells respond to intrinsic or extrinsic factors when maintaining specific tissue junctions.