Extensive modulation of inflammatory and axonal genes led to robust axon regeneration in severe benzalkonium chloride-injured corneas treated with cord blood-derived biologics

Modern ophthalmic solutions contain benzalkonium chloride (BAK), a potent antimicrobial preservative, that chronically damages the ocular apparatus. Umbilical cord blood serum (UCS) and platelet-rich plasma (UCPRP) are promising treatments for BAK-injured corneas. Here, for the first time, the feasibility of using both of these biologics for corneal treatment was demonstrated. Using animal studies and RNA-seq analysis, it was validated that severe BAK injury led to the upregulation of innate and adaptive immune responses, which corresponded to morphological and pathological changes in the cornea. When UCS and UCPRP were administered, besides significant corneal recovery, widespread immune pathways downregulation was observed. Subsequent verification of some of the genes involved in two of the most notable KEGG pathways suggested that the amelioration of inflammation was likely due to the reduction of immune cells, the decrease in chemoattractants, as well as the lessening of pro-inflammatory MMPs. Besides that, regulation of several key axonal genes led to robust axon recovery that correlated to nearly restored corneal sensitivity. Thus, these findings demonstrated the viability of cord blood-derived therapeutics for treating sustained, BAK-induced injuries in the cornea and also provided evidence that an optimal level of inflammatory response is crucial for stimulating axon regeneration.