Multiple types of retina cells have been produced from two types of stem cells by University of Wisconsin-Madison researchers. The finding gives new hope that damaged retinas may soon come to be repaired by cells grown from the patient's own skin.
The researchers have also said that their discovery may soon lead to laboratory models for studying genetically linked eye conditions, screening new drugs to treat those conditions and understanding the development of the human eye.
"This is an important step forward for us, as it not only confirms that multiple retinal cells can be derived from human iPS cells using the Wisconsin approach, but also shows how similar the process is to normal human retinal development," says David Gamm, an assistant professor of ophthalmology and visual sciences, who led a Waisman Center research team along with Jason Meyer, a research scientist
"That is quite remarkable given that the starting cell is so different from a retinal cell and the whole process takes place in a plastic dish. We continue to be amazed at how deep we can probe into these early events and find that they mimic those found in developing retinas. Perhaps this is the way to close the gap between what we know about building a retina in mice, frogs and flies with that of humans," he adds.
Meyer says the retina project began by using embryonic stem cells, but incorporated the induced pluripotent stem (iPS) cells-human stem cells made from skin-as they became available.
Ultimately, the group was able to grow multiple types of retina cells beginning with either type of stem cell, starting with a highly enriched population of very primitive cells with the potential to become retina.
The retina develops from a group of cells that arise during the earliest stages of the developing nervous system.
The Wisconsin team took cells from skin, turned them back into cells resembling embryonic stem cells, and then triggered the development of retinal cell types.
"This is one of the most comprehensive demonstrations of a cell-based system for studying all of the key events that lead to the generation of specialized neural cells. It could serve as a foundation for unlocking the mechanisms that produce human retinal cells," Meyer says.
Following their success in using the iPS cells, the researchers are expecting that their advance will lead to studying retinal development in detail, and treating conditions that are genetically linked.
They hope that someday ophthalmologists may be able to repair damage to the retina by growing rescue or repair cells from the patient's skin.
Earlier this year, scientists from the University of Washington showed that human ES cells had the potential to replace retinal cells lost during disease in mice.
"We're able to produce significant numbers of photoreceptor cells and other retinal cell types using our system, which are lost in many disorders," Meyer says.
The study has been published in the Proceedings of the National Academy of Sciences.