Morphological characteristics of corneal stromal stem cells and their age-related decline.

UNLABELLED: The corneal limbus contains limbal epithelial stem cells, stromal stem cells (SSCs), and stromal cells (SCs), which collectively contribute to the regeneration and maintenance of corneal epithelial integrity and transparency. However, the functional relationship among these three cell types remains unclear. The aim of this study was to investigate their morphological characteristics, potential inter-cell-type transformation mechanisms, and age-related alterations in these processes in the mouse corneal limbus. Keratocan-positive stromal cells (keratocytes) were predominantly localized in the posterior cornea and exhibited telocyte features, including expression of CD34, PDGFRα, and NG2. In contrast, SCA-1- and CD90-positive stromal stem cells were primarily distributed in the anterior stroma, where they maintained contact with stromal processes and extended toward the epithelial basal layer. A subset displayed epithelial stem cell-like features, consistent with a mesenchymal–epithelial transition-like process within the limbal niche. Aging (to 2 years) in mice was associated with reduced SSC numbers and morphological alterations, suggesting a potential decline in niche-associated regenerative capacity. Together, these findings clarify the spatial organization and cellular interactions within the limbal microenvironment and provide a foundation for developing SSC-based strategies for ex vivo corneal epithelial regeneration.

SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1038/s41598-026-50744-3.