Will stem cell research free blind mice?

Stem cells grown "in a dish" can integrate into the back of the eye in night-blind mice, according to a new study from University College London.

Prof Robin Ali and colleagues grew mouse embryonic stem cells in a three-dimensional synthetic retina and encouraged them to develop as light-sensitive cells called photoreceptors, which play a crucial role in sight. In degenerative eye diseases, loss of photoreceptors can lead to blindness.

When the scientists transplanted the stem-cell-derived photoreceptors into night-blind mice, a small number of the cells integrated into the retina at the back of the eye, they report in Nature Biotechnology this week.

The three-dimensional culture system meant it was possible to create "immature synthetic retinae in a dish" that were perfect for extracting immature photoreceptors for transplanting into the mice, explains researcher Prof Ali of UCL's Institute of Ophthalmology and Moorfields Eye Hospital.

It wasn’t possible to say whether transplanting the cells improved vision, but bumping up the numbers should shed more light on the situation, according to Ali, who is chief scientific advisor with Irish charity Fighting Blindness.

“We need to optimise the procedures so that we achieve a higher number of integrated photoreceptors,” he says. “We can then determine whether we improve vision - something I am confident of if we have sufficient cells, as we have shown this using donor photoreceptor cells from immature mouse retina.”

The research is still at a basic level, but to move towards the clinic the scientists are now working with human stem cells, including induced pluripotent stem cells derived from non-embryonic sources.

Prof Ali estimates that they may make regulatory applications in about three years and “aim to begin the first clinical trial in five years.”