(Cox News Service) -- In a pig's eye.

That's where scientist Michael Young believes he might find a cure for macular degeneration, an age-related disease that leads to the loss of central vision.

In late February, the neurobiologist and five of his colleagues at the Harvard-affiliated Schepens Eye Research Institute in Boston will fly to Copenhagen, Denmark, to start a year of clinical trials involving the curly-tailed animals.

The clinical tests will be performed in conjunction with University of Copenhagen's Panum Institute staff and a Swedish researcher, to determine if stem cells transplanted into a diseased eye can help restore sight. Stem cells are undifferentiated cells that can form into cells with specific functions.

About three years ago, Young and his colleagues began transplanting stem cells from healthy mice into mice with diseased eyes. Because the subjects are so small, the surgery is difficult to perform and the results are hard to determine. For a year, the team has experimented with transplanting the retinal stem cells of mice into pigs. The scientists found that some of the transplanted cells partially transformed into retinal cells. But the immune system of the pigs eventually rejected the mice stem cells.

"They didn't turn completely into the type of cells we wanted them to mainly because they didn't survive long enough," Young said.

Young said he hopes his team will find a way to control the process so that the stem cells fully transform into retinal cells and connect themselves to the optic nerve.

Copenhagen was selected as a site for research into pig-to-pig stem cell retinal transplants because researchers there have experience with the procedure - and Denmark is a major producer of pigs. "The pork industry is one of their biggest exports," Young said.

Young said he hopes the research with pigs - whose eye structure and size are similar to that of humans - will prove fruitful. The idea is to study the process' applicability in humans, not to lead to pig-to-human stem cell transplants. The two species are discordant, though the research will also involve transplanting human stem cells into pigs. "What we can do is study the human cells in the pig transplant setting, develop the human cells for use in humans," Young said.

Human stem cells for the research will be obtained from eye donors through organizations such as the Lion's Eye Bank and the Children's Hospital of Orange County, Calif., not from embryonic tissue, Young said. A small donation can go a long way as harvested stem cells can be grown into billions more cells in the laboratory, he said.

"It is certainly years off at this point but we have hopes that someday we will be able to restore vision to somebody who's been blinded," Young said.

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