Extracellular Vesicles for Corneal Endothelial Repair.

The corneal endothelium is essential for maintaining corneal transparency and visual function through regulation of stromal hydration. However, human corneal endothelial cells have limited regenerative capacity in vivo, and their loss due to aging, trauma, surgery, or diseases such as Fuchs endothelial corneal dystrophy can lead to corneal oedema and visual impairment. Although corneal transplantation remains the primary treatment for endothelial dysfunction or loss, donor tissue shortages and postoperative complications have driven the search for alternative therapies. Extracellular vesicles (EVs) have emerged as promising cell-free therapeutic agents that mediate intercellular communication through the transfer of bioactive molecules. Recent studies have investigated two distinct EV sources in corneal endothelial biology: mesenchymal-stem-cell-derived EVs, which have demonstrated cytoprotective and regenerative effects, and corneal endothelial cell-derived EVs, which appear to modulate endothelial homeostasis and, depending on their cargo, may either limit proliferation or exert protective effects. This review summarizes current evidence on EV biology, their distinct cellular sources, and their potential roles in corneal endothelial repair.