Tuesday December 6, 2005

Researchers Make Breakthrough in Lens Regeneration

Researchers Grow New Lens From Deficient Iris Tissue For First Time; Published In Leading Scientific Journal.

The fact that salamanders can re-grow certain body parts has amazed and confounded scientists for centuries. When it comes to lens regeneration in these animals, the fact that the lens is regenerated from the dorsal iris but not the ventral iris has been a puzzle, which finally may be solved.

Now, a team of researchers lead by University of Dayton biology professor Panagiotis Tsonis, for the first time has been able to manipulate key genes in the ventral iris to regenerate a new lens. This research means scientists may one day be able to re-grow lenses in other animals and eventually humans, which could dramatically reduce the need for cataract procedures. The research is published in the Dec. 8 issue of Nature.

"The ventral iris, which is the bottom part of the iris, is never able to regenerate a lens, despite the fact that it contains the same cells as the dorsal iris," Tsonis said. "We managed to regenerate a lens from the ventral iris by manipulating the expression of key genes, which provides evidence for the first time that lens regeneration from a noncompetent iris is possible. Apart from answering a fundamental biological question in the regeneration field, our results indicate that inducing lens regeneration in other animals might be possible by manipulating their iris cells."

The hope is that someday lens regeneration in humans will be possible, as well as the regeneration of other organs. Tsonis cautions, however, that it will be many years before such procedures may be possible.

All the research took place in UD science labs through funding by the National Institutes of Health. Other members of the research team include Matthew Grogg and Mindy Call, graduate students in biology at UD and also first authors of the research; Mitsumasa Okamoto, a collaborating professor at Nagoya University in Japan; Katia Del Rio-Tsonis, professor, and Natalia Vergara, a graduate student, at Miami University.

Professor Tsonis has been conducting research on lens and limb regeneration for more than 10 years at UD. The National Eye Institute, through the NIH, has funded the research throughout that time. This latest discovery will be indispensable for cataract research, surgery and therapy, considering more than 350,000 cataract operations are performed in the United States every year. And, nearly half of all cataract patients need a second surgery to retain their vision.

"In traditional cataract surgery, doctors take out the old lens and replace it with a synthetic lens in the lens capsule," Tsonis said. "Because some cells remain, they can start proliferating and make the lens opaque over time, creating the need for a second cataract surgery. This would be alleviated if humans could regenerate their lenses."

And, maybe someday, they will.

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