Editors' ChoiceTissue Engineering

Let There Be Light: Next-Generation Artificial Corneas

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Science Translational Medicine  24 Feb 2010:
Vol. 2, Issue 20, pp. ec31
DOI: 10.1126/scitranslmed.3000984

According to the World Health Organization, damage to the cornea—the transparent outer covering of the eye—ranks as the fourth leading cause of blindness globally and gives rise to ~90% of blindness in economically underdeveloped countries, where half of a million new cases arise annually in children. Corneas can suffer irreversible scarring as a result of trauma or disease (for example, trachoma, a common bacterial infection of the eye). For heavily damaged corneas, the current best treatment is cornea transplantation, but a shortage of donor organs worldwide hampers use of this site-restoring therapy. Now, McLaughlin et al. report progress in the engineering of multifunctional artificial corneas for transplantation.

In addition to providing a protective window for light transmission, the cornea contains nerve endings that are sensitive to temperature and touch and impart an eyelid-closing involuntary reflex. Currently available artificial corneal substitutes protect and restore light transmission to the eye but do not reconstitute innervation or sensory function of the organ. Using a guinea pig model, McLaughlin et al. sought to demonstrate that an implanted artificial next-generation, collagen-based cornea could undergo functional innervation. The researchers detected nerve activity in the implants in as early as 3 months after transplantation into the animals. And after 6 months, corneal transparency and light transmission were restored. By 8 months after surgery, the in-grown corneal nerves displayed normal conduction velocity and nociception—detection of potentially harmful stimuli—responding to thermal, mechanical, and CO2 stimulation. These promising results suggest that it is possible to develop fully functional replacement corneas that can then be used to restore vision to afflicted people around the world.

C. R. McLaughlin et al., Regeneration of functional nerves within full thickness collagen–phosphorylcholine corneal substitute implants in guinea pigs. Biomaterials 31, 2770–2778 (2010). [Abstract]

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