Stem Cells for Corneal Engineering

描述：人口老龄化和屈光手术的普及威胁着美国用于移植的角膜供应的充分性。在世界范围内，角膜捐赠已经短缺，导致600-800万人患有角膜失明。在实验室中培养并按需提供的工程角膜最终将有助于缓解这一公共卫生问题。该项目的长期目标是利用培养的人类干细胞开发用于移植的角膜替代物。最初，该项目将专注于角膜基质，即占角膜质量90%的结缔组织。我们最近发现了一组来自人类角膜基质的细胞，具有成体干细胞的特性。与角膜基质细胞不同的是，人角膜基质干细胞(HCSSC)在培养过程中可以多次传代，但在体内和体外仍具有成为角膜基质细胞的能力。我们假设人角膜基质干细胞参与了角膜损伤的反应，并能在体内和体外再生透明的基质组织。这一假说将通过以下两个方面得到验证：(1)通过证实hCSSC进入病理性的人类角膜，以及通过记录hCSSC在体内导入正常和愈合的小鼠角膜的命运。(2)对于形成类似于角膜瘢痕的混浊和注射转化生长因子β后形成的角膜瘢痕，用hCSSC治疗，以观察这些细胞恢复角膜透明度的能力。(3)将hCSSC体外制备的组织等效物植入小鼠角膜，研究其对基质组织透明性的分子和结构要求。这些目标的成功实现将阐明新发现的成人基质干细胞的生物学作用，并为体内如何维持基质超微结构和角膜透明度提供新的信息。这些实验还将开发基于细胞的治疗角膜疤痕和制造可直接用于板层的生物工程组织的基本技术。 角膜移植或作为完全生物工程角膜的基础。

DESCRIPTION: 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.