A micro-contoured contact lens for delivering 3D-printed ABCB5-positive stem cells for corneal regeneration

Abstract

Purpose : Limbal stem cells (LSC) residing in the limbus continually repopulate the corneal epithelium. Limbal stem cell deficiency (LSCD) occurs when these LSC are damaged or missing. Patients with LSCD are unable to regenerate the corneal epithelium, resulting in blindness due to invasion of the conjunctiva and neovascularization. While tissue from the unaffected eye can be used to treat unilateral LSCD, patients with bilateral LSCD as well as those with inflammation and severe pathologies would greatly benefit from an alternative autologous source of stem cells as allogeneic transplants are associated with poor outcomes and require lifelong immunosuppression. We previously demonstrated that human ABCB5+ LSC were capable of restoration of the corneal epithelium in an NSG mouse model of LSCD. We found that ABCB5 is also expressed by skin stem cells and hypothesized that these dermal cells could provide an alternative source of stem cells for corneal regeneration.

Methods : We first tested the ability of human ABCB5+ dermal stem cells (DSC) expanded in vitro and purified by cell sorting to transform into corneal epithelial cells when cultured in corneal differentiation media. Next, we tested the ability of ABCB5+ DSC to regenerate clear corneas when transplanted onto NSG mice with mechanically induced LSCD. We are currently scaling up to a rabbit model of LSCD and using a 3D bioprinter to seed ABCB5+ DSC on a custom-designed contact lens created from eye impression technology.

Results : Human ABCB5+ DSC were induced in vitro to express significant levels of PAX6 and KRT12. Mice transplanted with human ABCB5+ DSC had clearer corneas compared to controls (Fig 1). Using eye impression technology, we created custom contact lenses modified to accommodate bioprinted ABCB5+ DSCs (Fig 2).

Conclusions : Our results support the use of ABCB5+ DSC as an alternative autologous source of stem cells to regenerate the corneal epithelium. Delivery of these cells using 3D bioprinting and custom contact lenses is promising for robust regeneration of the ocular surface.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

 

ABCB5+ DSC transplanted onto NSG mice with mechanically induced LSCD.

 

A. Ocular surface impression of a rabbit eye. B. Software interface for creating custom contact lens. C. Bioprinting of ABCB5+ DSC in fibrin gel in limbal ring. D. ABCB5+ DSC bioprinted onto a custom contact lens created from an ocular surface impression.