Abstract
Purpose :
Human mesenchymal stem cells (hMSC) applied to the wounded eye have been shown to improve the rate of wound healing possibly due to the paracrine factors produce by these cells (the secretome). We hypothesized that combining secretome and HA would provide a synergistic effect on corneal wound healing over topical delivery of the secretome alone. Here we aim to deliver the hMSC secretome to the corneal surface using a viscous gel formulation of hyaluronic acid (HA) and chondroitin sulfate (CS) as a vehicle.
Methods :
Conditioned media was produced, collected and lyophilized from bone marrow-derived hMSCs. Primary rabbit corneal epithelial cells (CECs) at passage two were starved for 12 hours, and then the various treatments were added. Lyophilized secretome and HA/CS were serially diluted in phosphate buffered saline (PBS) down to 0.01 mg/mL. At 24, 48 and 72 hours, cell proliferation was measured using a cell counting kit. The same assay was repeated for a mixture of secretome and HA/CS with the optimal concentrations that had been determined for each component individually. For in vivo assay in mice, 2 mm mechanical corneal epithelial debridements were performed, followed by 20 μL of the various treatments to each injured cornea (secretome with HA/CS gel carrier, secretome alone, HA/CS gel carrier alone, and PBS) . After 24 and 48 hours, the corneas were stained with fluorescein and photographed. The wound size was analyzed using Image J.
Results :
Secretome concentration between 7.5 and 1 mg/mL statistically significantly improved cell proliferation. HA/CS alone performed better at higher concentrations. When mixed and applied together, secretome and HA/CS increased cell proliferation and survival at 48 and 72 hours compared to the each substance alone. The same result was observed in vivo; while no statistically significant improvement in wound closure was observed for the HA/CS gel and secretome alone compared to saline controls, when the secretome was applied with the HA/CS gel carrier, wound closure was nearly 100% at 24 hours (p<0.01).
Conclusions :
The results obtained showed that the hMSC secretome and HA/CS may have synergistic effects on epithelial cell proliferation and corneal wound closure after mechanical injury compared to either the secretome or HA/CS gels alone.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.