Potential Therapeutic Effects of Epithelial and Mesenchymal Stem Cell Secretome in Benzalkonium Chloride-Induced Limbal Stem Cell Dysfunction.

Dry Eye Disease (DED) is a multifactorial condition of the ocular surface, with one potential cause being damage from eye drops containing preservatives such as benzalkonium chloride (BAC). Current treatments for DED are unsatisfactory; therefore, it is worth exploring new therapies based on the secretome derived from stem cells. Human stem cells are important sources of growth factors and cytokines that promote tissue regeneration. The secretome of these cells can be obtained in vitro in conditioned medium (CM). The aim of the study was to evaluate the effect of CM derived from adipose-derived stem cells (hADSCs) and amniotic membrane-derived cells expressing mesenchymal and/or epithelial markers on limbal stem cells (LSCs) damaged by BAC, focusing on their regenerative potential. The study used two experimental models: the first focused on neutralizing the toxic effects of BAC when each CM was administered concurrently, and the second on the therapeutic effects of CM after prior cell damage by BAC. The effects of CM on LSCs were assessed, including apoptosis, cell cycle progression, proliferation, migration, and inflammation. CM from ADSCs and amniotic cells were shown to significantly reduce BAC-induced damage to LSCs. All tested CM promoted LSC regeneration, although their efficacy varied among treatments. The application of CM during BAC exposure yielded stronger and more consistent benefits than post-injury treatment.