The Effect of Bone Marrow Mesenchymal Stem Cell Secretome on Corneal Epithelial Wound Healing

Abstract

Purpose : The corneal epithelium protects the eye against pathogen invasion and plays an essential role in preserving corneal clarity. Following injury to the corneal epithelium, the epithelial cells undergo a highly coordinated repair process involving migration, proliferation and differentiation. Mesenchymal stem cells (MSCs) have been shown to modulate the wound healing response in a number of tissues. The regenerative effects of MSCs appear to be mostly mediated through paracrine mechanisms via their secretome. We evaluated the effect of bone marrow derived MSC secretome on corneal epithelial wound healing.

Methods : Bone-marrow derived MSCs were isolated from healthy donors and cultured in MEM-alpha with 10% fetal bovine serum. Passage 4 to 6 MSCs were used for the experiments. All experiments were repeated with at least five different donors. After reaching confluency, the media was changed to serum free MEM-alpha. The secretome was collected after 48 hours. It was normalized based on total protein content. Scratch assay was performed on telomerase-immortalized human corneal epithelial cells (HCEC) to evaluate in vitro wound closure in the presence of either MSC secretome or MEM- alpha. Six-month-old C57BL/6J mice were used to study corneal wound healing in vivo. A 1.5-mm area of the central epithelium was demarcated and removed by gentle scraping using a blunt corneal scraper and the cornea was subsequently treated with MEM-alpha or MSC secretome for 30 minutes. The eyes were serially photographed under a slit lamp microscope every 12 hours.

Results : Mechanically wounded HCECs that were incubated in MSC secretome had 4.3 ± 3.5 percent remaining wound area after 16 hours while MEM-alpha had 39.5 ± 5.2 percent (P <0.001). After 24 hours, 43.2 ± 12.4 percent of MSC secretome treated mice had complete corneal wound healing compared to 24.6 ± 21.2 percent in MEM- alpha group (P <0.001).

Conclusions : MSC secretome contains factors that can accelerate corneal epithelial wound healing. It may be used therapeutically in ocular surface diseases such as persistent corneal epithelial defects.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.