Researchers have grown part of an eye in a lab dish, using a type of stem cell made from a piece of skin.
They said the little retina started growing and developing on its own - an important step towards creating custom-tailored organs in the lab.
'We have basically created a miniature human retina in a dish that not only has the architectural organization of the retina but also has the ability to sense light,' said M. Valeria Canto-Soler, an assistant professor of ophthalmology at the Johns Hopkins University School of Medicine.
The team used cells called induced pluripotent stem cells, or iPS cells, which are immature stem cells whose powers resemble those of embryonic stem cells - they can morph into any cell type in the body.
They're made by tricking an ordinary cell, like a skin cell, into reverting back into embryonic mode. Then the researchers activate genes to get the cell to redirect itself into forming the desired cells - in this case cells of the retina.
To the surprise of the researchers, the cells started developing as if they were in a growing human embryo.
'We knew that a 3-D cellular structure was necessary if we wanted to reproduce functional characteristics of the retina, but when we began this work, we didn't think stem cells would be able to build up a retina almost on their own. In our system, somehow the cells knew what to do,' Canto-Soler said in a statement.
The experiment 'may ultimately lead to technologies that restore vision in people with retinal diseases,' she added.
Tests showed the cells responded to light, the team reported in the journal Nature Communications. 'Is our lab retina capable of producing a visual signal that the brain can interpret into an image? Probably not, but this is a good start,' Canto-Soler said.
Other teams have used iPS cells to make a piece of human liver and are using them to study a range of human diseases.
First published June 10 2014, 9:58 AM
Maggie Fox is senior health writer for NBCNews.com and TODAY.com, writing top news on health policy, medical treatments and disease. She's a former managing editor for healthcare and technology at National Journal and global health and science editor for Reuters based in Washington, D.C. and London.She's reported for news agencies, radio, newspapers, magazines and television from across Asia, the Middle East, Africa and Europe covering news ranging from war to politics and, of course, health and science. Her reporting has taken Maggie to Lebanon, Syria and Libya; to China, South Korea, Thailand, the Philippines and Pakistan; to Bosnia, Croatia and Serbia and to Ireland and Northern Ireland and across the rest of Europe.Maggie has won awards from the Society of Business Editors and Writers, the National Immunization Program, the Overseas Press Club and other organizations. She's done fellowships at Harvard Medical School, the National Institutes of Health and the University of Maryland.