导读：新眼角膜(cornea)移植可能是阻止病人眼睛变瞎的唯一方法，但是捐献的角膜存在短缺，因而排队等待角膜移植的队伍比较长。来自瑞典哥德堡大学萨尔格学院(Sahlgrenska Academy)的科学家第一次成功地在人角膜上培养干细胞，并且长期而言，这可能导致人们不再需要捐献者捐献角膜。
在瑞典，每年需要进行大约500例角膜移植手术，而在全世界则这一数字大约是10万。角膜受损和变得浑浊将让病人变瞎，但是它能够被一个健康和透明的角膜替换。但是这种过程需要一个捐献的角膜，只是捐献的角膜严重短缺。在全世界，这种情形也是如此，尤其是一些宗教或政治观点经常阻碍人们使用捐献的角膜的地方。
替换捐献的眼角膜
来自萨尔格学院的科学家朝利用干细胞培育的眼角膜替换捐献的眼角膜的最终目标迈出了第一步。科学家Charles Hanson和Ulf Stenev所i使用的缺陷性眼角膜是从默恩达尔市萨格林斯卡大学附属医院(Sahlgrenska University Hospital in Mölndal)眼科门诊获得的。他们的研究结果发表Acta Ophthalmologica在期刊上，而且表明他们先在实验室培养16天接着在角膜上培养6天后能够让人干细胞变成“上皮细胞(epithelial cell)”。而正是上皮细胞维持眼角膜的透明。
第一次在人角膜上培养干细胞
“类似的实验在动物上进行过，但是这是第一次让干细胞在人受损角膜上生长。它意味着我们朝能够使用干细胞治疗受损角膜的最终目标迈出了第一步”，Charles Hanson说。“如果我们能够为此建立一种常规的方法，那么就可以给需要角膜的病人提供无穷无尽的新角膜。移植手术程序和术后护理也将变得更加简单”，Ulf Stenevi说。
只有少数诊所能够进行角膜移植
当前只有一些诊所能够开展角膜移植手术。在瑞典，很多角膜移植手术是在萨格林斯卡大学附属医院眼科门诊完成的。
Transplantation of human embryonic stem cells onto a partially wounded human cornea in vitro
Charles Hanson, Thorir Hardarson, Catharina Ellerström, Markus Nordberg, Gunilla Caisander, Mahendra Rao, Johan Hyllner, Ulf Stenevi
Purpose: The aim of this study was to investigate whether cells originating from human embryonic stem cells (hESCs) could be successfully transplanted onto a partially wounded human cornea. A second aim was to study the ability of the transplanted cells to differentiate into corneal epithelial-like cells.
Methods: Spontaneously, differentiated hESCs were transplanted onto a human corneal button (without limbus) with the epithelial layer partially removed. The cells were cultured on Bowman’s membrane for up to 9 days, and the culture dynamics documented in a time-lapse system. As the transplanted cells originated from a genetically engineered hESC line, they all expressed green fluorescent protein, which facilitated their identification during the culture experiments, tissue preparation and analysis. To detect any differentiation into human corneal epithelial-like cells, we analysed the transplanted cells by immunohistochemistry using antibodies specific for CK3, CK15 and PAX6.
Results: The transplanted cells established and expanded on Bowman’s membrane, forming a 1–4 cell layer surrounded by host corneal epithelial cells. Expression of the corneal marker PAX6 appeared 3 days after transplantation, and after 6 days, the cells were expressing both PAX6 and CK3.
Conclusion: This shows that it is possible to transplant cells originating from hESCs onto Bowman’s membrane with the epithelial layer partially removed and to get these cells to establish, grow and differentiate into corneal epithelial-like cells in vitro.
