Stem Cells for Corneal Engineering

人口老龄化和屈光手术的普及威胁着角膜供应的充分性 在美国进行移植。在世界范围内，眼角膜捐赠已经短缺，剩下600-800万人 患有角膜失明。在实验室培养并按需提供的工程化角膜将 最终有助于缓解这一公共卫生问题。这个项目的长期目标是开发角膜 使用培养的人类干细胞进行移植的等价物。最初，该项目将专注于角膜 基质，构成角膜质量90%的结缔组织。我们最近发现了一种 具有成体干细胞特性的人角膜基质细胞群。与角质形成细胞不同， 人角膜基质干细胞(HCSSC)可以在培养中多次传代，但仍能保留 在体内和体外成为角质形成细胞的能力。我们假设人类角膜基质干细胞 参与角膜损伤的反应，并能在体内和体内再生透明的间质组织 试管婴儿..这一假设将被检验(1)通过证明hCSSC进入病理性人类体内 并通过记录hCSSC导入正常和正在愈合的小鼠体内角膜的命运。 (2)LUMICAN缺陷型小鼠，出现与角膜疤痕相似的混浊现象，并通过注射 转化生长因子β将与hCSSC一起处理，以研究观察到的这些细胞的能力 恢复角膜透明度。(3)hCSSC体外生产的组织等效物将被植入 研究小鼠角膜基质组织透明度的分子和结构要求。 这些目标的成功实现将阐明新发现的成体基质的生物学作用 干细胞，并提供有关基质超微结构和角膜透明度的新信息 在体内维持。这些实验还将开发基于细胞的治疗的基本技术。 角膜疤痕和可直接用于板层的生物工程组织的制造 角膜移植或作为完全生物工程角膜的基础。

Aging of the population and popularity of refractive surgery threaten adequacy of the cornea supply used for transplantation in the USA. World-wide, cornea donations already fall short, leaving 6-8 million individuals suffering corneal blindness. Engineered corneas, grown in the laboratory and available on demand, will ultimately help alleviate this public health problem. The long-term goal of this project is to develop corneal equivalents for transplantation using cultured human stem cells. Initially the project will focus on the corneal stroma, the connective tissue that makes up 90% of the corneal mass. We have recently discovered a population of cells from human corneal stroma with properties of adult stem cells. Unlike keratocytes, the human corneal stromal stem cells (hCSSC) can be passaged numerous times in culture but still retain the ability to become keratocytes in vivo and in vitro. We hypothesize that the human corneal stromal stem cells participate in response to corneal injury and can regenerate transparent stromal tissue both in vivo and in vitro.. This hypothesis will be tested (1) by demonstrating the influx of hCSSC into pathological human corneas and by documenting the fate of hCSSC introduced into normal and healing mouse corneas in vivo. (2) Lumican null mice which develop opacity similar to corneal scars and corneas scarred by injection of transforming growth factor beta will be treated with hCSSC to investigate observed ability of these cells to restore corneal transparency. (3) Tissue equivalents produced in vitro by hCSSC will be implanted into mouse cornea to investigate the molecular and structural requirements for transparency in stromal tissue. Successful accomplishment of these aims will elucidate biological roles of the newly discovered adult stromal stem cells and provide novel information about how the stromal ultrastructure and corneal transparency are maintained in vivo. The experiments will also develop essential technologies for cell-based therapy for corneal scars and for fabrication of bioengineered tissue which could be used directly for lamellar keratoplasty or serve as the basis of a fully bioengineered cornea.