Keeping an eye on decellularized corneas: a review of methods, characterization and applications

Abstract

The worldwide limited availability of suitable corneal donor tissue has led to the development of alternatives, including keratoprostheses (Kpros) and tissue engineered (TE) constructs. Despite advances in bioscaffold design, there is yet to be a corneal equivalent that effectively mimics both the native tissue ultrastructure and biomechanical properties. Human decellularized corneas (DCs) could offer a safe, sustainable source of corneal tissue, increasing the donor pool and potentially reducing the risk of immune rejection after corneal graft surgery. Appropriate, human-specific, decellularization techniques and high-resolution, non-destructive analysis systems are required to ensure reproducible outputs can be achieved. If robust treatment and characterization processes can be developed, DCs could offer a supplement to the donor corneal pool, alongside superior cell culture systems for pharmacology, toxicology and drug discovery studies.

Figure 1

Schematic representation of physical decellularization protocols.

Figure 2

(A) Native corneal structure and cellular nuclear staining using hemotoxylin and eosin staining; and (B) DAPI.

Figure 3

Basic macroscopic evaluation of decellularized corneas can provide a crude marker of the success of a decellularization protocol; comparisons of (A) a non-treated cornea; versus (B) a cornea treated with strong ionic detergents. It is apparent that the detergent-treated cornea is opaque in appearance when compared to the transparent non-treated cornea. These opacities are caused by disruption of the tissue architecture due to the decellularization process.

Figure 4

False-colored images of corneal stromal cells (blue) and collagen structure in tissue-engineered corneal stromal constructs at relatively (A) high; and (B) low magnification imaged using SEM.

Figure 5

Schematic representation of in vivo recellularization techniques.

Figure 6

Schematic representation of ex vivo recellularization techniques.