Table 1.

Corneal Stromal Cells, Derivation and Phenotype

Cell Type	Cell Derivation	Phenotype
Neural Crest Cells	Neural Ectoderm During neural tube closure	They migrate throughout the developing embryo and contribute to the development of a number of different organs including the eye. The corneal stroma and endothelium are neural crest derivatives
Keratoblasts	Neural Crest Cells That migrate between the corneal epithelium and endothelium during development	They proliferate and produce a hyaluronan-rich ECM containing sparse collagen fibrils
Keratocytes	Keratoblasts	They replace the hyaluronan-rich ECM with an ECM consistent with transparency containing densely packed collagen fibrils and proteoglycans during late embryonic and post natal development
Quiescent Keratocytes	Keratocytes	They have a low level of biosynthetic activity to maintain the ECM produced by keratocytes
Hypercellular Myofibroblasts	Keratocytes/Quiescent Keratocytes	They contain α smooth muscle actin, but produce only low levels of ECM resulting in densely packed cells in a sparse ECM
Myofibroblasts	Hypercellular Myofibroblasts	They contain α smooth muscle actin and produce high level of ECM, but containing components such as hyaluronan that are not normally present resulting in an ECM inconsistent with transparency
Wound Fibroblasts	Hypercellular Myofibroblasts Possibly Myofibroblasts	They produce an ECM of densely packed fibrils and proteoglycans that restores transparency
Corneal Fibroblasts	Keratocytes/Quiescent Keratocytes	Result from cell culture in media containing fetal bovine serum. A varying proportion contain α smooth muscle actin