Division of Ophthalmology and Visual Sciences, University of Nottingham, Queen's Medical Centre Campus, Nottingham, UK.
Invest Ophthalmol Vis Sci. 2012 Aug 3;53(9):5109-16. doi: 10.1167/iovs.11-8673.
Peripheral and limbal corneal stromal cells (PLCSCs), which contain keratocytes, have a complex phenotype. Knowledge of keratocyte cell properties, function, and origin is limited. Evidence available thus far has suggested both mesenchymal stromal and hematopoietic characteristics. Multipotent mesenchymal stromal cells (MSCs) are found in an increasing number of tissues and are the subject of considerable interest and investigation in the disciplines of tissue engineering, immunology, gene therapy, and oncology.
Isolated PLCSCs were characterized by markers aldehyde dehydrogenase and keratocan, cultured, and analyzed against a set of criteria for the identification of MSCs developed by the International Society of Cellular Therapy (ISCT). PLCSCs were directly compared to fetal liver MSCs (flMSCs). Additional cell surface markers were also used to quantify differentiation, which was also performed on both cell types.
PLCSCs were found to be plastic adherent, displayed the correct profile and proportions of CSMs, and demonstrated trilineage potential in accordance with the ISCT guidelines. Furthermore, PLCSCs displayed a high degree of similarity to flMSCs and this likeness extended into the non-ISCT MSC cell surface markers and trilineage differentiation, which were often but not always comparable.
Herein we report a novel observation that PLCSCs conform to all the ISCT criteria and are therefore MSCs. Furthermore, this study has identified the limbal stroma as yet another MSC niche and presents a new perspective on the role of the PLCSC.
含有角膜基质细胞（keratocytes）的外周和角膜缘角膜基质细胞（PLCSCs）具有复杂的表型。对角膜基质细胞的特性、功能和来源的了解有限。迄今为止的证据表明，它们既有间充质基质细胞又有造血细胞的特征。多能间充质基质细胞（MSCs）存在于越来越多的组织中，并且是组织工程学、免疫学、基因治疗学和肿瘤学等学科中相当关注和研究的对象。
通过醛脱氢酶和角膜蛋白聚糖等标志物对分离的 PLCSCs 进行特征描述，培养并根据国际细胞治疗学会（ISCT）制定的 MSC 鉴定标准进行分析。将 PLCSCs 与胎肝间充质干细胞（flMSCs）直接进行比较。还使用了其他细胞表面标志物来量化分化，这两种细胞类型都进行了分化实验。
PLCSCs 具有塑料贴壁性，表现出正确的 CSM 特征和比例，并根据 ISCT 指南显示出三系潜能。此外，PLCSCs 与 flMSCs 高度相似，这种相似性扩展到非 ISCT MSC 细胞表面标志物和三系分化，这些标志物虽然常常但并不总是具有可比性。
本研究首次报道了 PLCSCs 符合 ISCT 所有标准，因此属于 MSC。此外，本研究还发现了角膜缘基质是另一个 MSC 龛位，并为 PLCSC 的作用提供了新的视角。
