Corneal Decellularization: A Method of Recycling Unsuitable Donor Tissue for Clinical Translation?

Abstract

Background: There is a clinical need for biomimetic corneas that are as effective, preferably superior, to cadaveric donor tissue. Decellularized tissues are advantageous compared to synthetic or semi-synthetic engineered tissues in that the native matrix ultrastructure and intrinsic biological cues including growth factors, cytokines and glycosaminoglycans may be retained. However, there is currently no reliable, standardized human corneal decellularization protocol. Methods: Corneal eye-bank tissue unsuitable for transplantation was utilized to systematically compare commonly used decellularization protocols. Hypertonic sodium chloride; an ionic reagent, sodium dodecyl sulphate; a non-ionic detergent, tert-octylphenol polyoxyethylene (Triton-X); enzymatic disaggregation using Dispase; mechanical agitation; and the use of nucleases were investigated. Decellularization efficacy, specifically for human corneal tissue, was extensively evaluated. Removal of detectable cellular material was evidenced by histological, immunofluorescence and biochemical assays. Preservation of macroscopic tissue transparency and light transmittance was evaluated. Retention of corneal architecture, collagen and glycosaminoglycans was assessed via histological, immunofluorescence and quantitative analysis. Biocompatibility of the resulting scaffolds was assessed using cell proliferation assays. Results: None of the decellularization protocols investigated successfully removed 100% of cellular components. The techniques with the least residual cellular material were most structurally compromised. Biochemical analysis of glycosaminoglycans demonstrated the stripping effects of the decellularization procedures. Conclusion: The ability to utilize, reprocess and regenerate tissues deemed “unsuitable” for transplantation allows us to salvage valuable tissue. Reprocessing the tissue has the potential to have a considerable impact on addressing the problems associated with cadaveric donor shortage. Patients would directly benefit by accessing greater numbers of corneal grafts and health authorities would fulfill their responsibility for the delivery of effective corneal reconstruction to alleviate corneal blindness. However, in order to progress, we may need to take a step back to establish a “decellularization” criterion; which should balance effective removal of immune reactive material with maintenance of tissue functionality.

Tissue‐engineering acellular scaffolds—The significant influence of physical and procedural decellularization factors

“…Additionally, this highlights a common problem: While thin tissues can be easily decellularized, central regions of thicker tissues are hardly reached by DC agents . In our experiments DAPI and H.E.…”

Characterization of decellularized ovine small intestine submucosal layer as extracellular matrix‐based scaffold for tissue engineering

“…Studies have shown that SDS and TX‐100 have a great ability to remove GAG of tissue. Therefore, researchers are trying to save GAG as much as possible in the matrix during the decellularization process . In this study, it has been revealed that there was a significant difference in GAG content of the untreated group compared to that of the treated groups.…”

Decellularization methods for developing porcine corneal xenografts and future perspectives

“…These studies suggest that TX alone is not a strong enough detergent to sufficiently decellularize corneas. On the other hand, since TX is not able to break protein‐to‐protein interactions, disruption of the histo‐architecture is not as complete as with SDS, and there remain reduced transparency and edema after use of TX …”

“…Hypertonic saline has been used to decellularize human, porcine, rabbit, and ostrich corneas . HS is an effective decellularization agent due to its ability to disrupt DNA‐to‐protein interactions and to induce osmotic lysis .…”