December 2, 2003.
By: JOHN INNES,
CORNEAS have successfully been grown around protein and plastic scaffolds planted into the eyes of partially blind pigs, scientists revealed yesterday.
The grafts regenerated the cells necessary to make a functioning cornea, including nerves.
Scientists believe that the breakthrough could lead to new treatments for millions of people who suffer from poor vision because of corneal damage.
The cornea is the transparent, light-refracting dome that covers the front of the eye.
If it loses transparency, vision can be permanently impaired. Corneal diseases affect more than ten million people worldwide.
The artificial cornea was made from a transparent matrix of collagen and a synthetic polymer, or plastic.
A team of scientists, led by May Griffith at the University of Ottawa Eye Institute in Canada, implanted the matrix into the eyes of pigs with damaged corneas.
New corneal tissue grew around the scaffold, including nerves which regenerated within three weeks.
Pigs receiving traditional donor transplants showed no nerve regeneration over the same time period.
The scientists wrote in the journal Proceedings of the Royal Academy of Sciences: "Other corneal substitutes have been produced and tested, but here we report an implantable matrix that performs as a physiologically functional tissue substitute and not simply as a prosthetic device.
"These biosynthetic ECM [extra-cellular matrix] replacements should have applicability to many areas of tissue engineering and regenerative medicine, especially where nerve function is required."
At present, the main treatment for corneal blindness is transplantation with human donor tissue.
But demand for donor tissue outstrips supply, and the lack of nerve regeneration after surgery can present problems. The nerves are necessary for maintaining overall corneal health. When corneal sensitivity is lost, the cornea becomes vulnerable to injury and ulceration.
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