Contacts:Don Sakaguchi, Zoology/Genetics, (515) 294-3112Brian Meyer, Agriculture Communications, (515) 294-0706, [email protected]
SUCCESS WITH MICE STEM CELLS ENCOURAGING FOR TREATING EYE DISEASE
AMES, Iowa -- In a positive sign for future treatment of human eye diseases, researchers from Iowa State University and Harvard Medical School found that transplanted mice cells successfully become integrated into the eyes of Brazilian opossums.
"The research is a promising step for using cell replacements to treat diseases of the human eye like glaucoma, macular degeneration and diabetic retinopathy," said Don Sakaguchi, a developmental neurobiologist and associate professor of zoology and genetics at Iowa State.
"The work also may have implications for treating brain disorders such as Parkinson's and Alzheimer's as well as injuries to the brain or spinal cord," said Sakaguchi, who reported on the research at the Society of Neuroscience's annual meeting in New Orleans, Nov. 4-9.
The transplanted cells were neural stem cells from mice. Stem cells are cells that the body has not yet assigned a specific identity. Biochemical and genetic signals cause stem cells to differentiate into liver cells, skin cells, nerve cells or other cell types.
Harvard scientist Michael Young and his colleagues engineered the mice stem cells so that they produced a fluorescent protein. Once the cells were transplanted into Brazilian opossums, the researchers could determine their fate by tracking the green-glowing protein.
The mice stem cells were transplanted into the eyes of opossums ranging from 10 days old to two years old. Eye tissue from the animals was examined after one to 12 weeks. The researchers found the transplanted cells differentiated into nerve cells and glial cells, cell types that are normally found in the eye.
In general, the researchers found that the younger the opossum, the greater the chance for stem cells to integrate and differentiate. "Experiments by other scientists have had limited success in integrating neural stem cells into adult animals," Sakaguchi said. "Our results suggest stem cells stand a better chance if they can be transplanted into an embryo-like environment."
That kind of environment is what the Brazilian opossum provides. The opossum's pea-sized newborns are very immature. "With the newborn opossum, we essentially have access to an embryonic stage of brain development," Sakaguchi said. "This makes the opossum a good model to study cellular connections in the brain as they become established."
The next step of the research will be to identify the conditions in this embryo-like environment that enhance the survival and differentiation of stem cells. With this information, researchers can try to mimic the conditions so stem cells stand a better chance for use in adult animals. In the future, the researchers would like to transplant stem cells into animals with eye or other brain disorders to see whether the cells help treat the disease.
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EDITOR'S NOTE: Don Sakaguchi will be in New Orleans through Nov. 9 at the Society of Neuroscience annual meeting. He will check phone and fax messages at the St. James Hotel, (504) 304-4000l; fax (504) 304-4444. He will be back in his office at Iowa State on Nov. 13. From Nov. 9-12, he will check e-mail messages [email protected].
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