Fishing for retinal healing solutions

A treatment that switches on retinal nerve healing within the human eye just became a step closer – thanks to fish.

Scientists at Heidelberg University are studying the Japanese rice fish’s ability to regenerate its retinal nerve cells after injury. Learning what switches on this process could eventually give medical researchers a way to trigger the process in the degenerated human eye in diseases like glaucoma.

As described in the journal Development, the team has found that the healing starts in the fish’s eye when specialised cells – known as Muller cells – congregate around the injury and start to divide. These cells form clusters in which new retinal nerve cells are generated.

Humans also have Muller cells within the eye, so it may be possible to activate the same process in a patient, paper co-author and developmental biologist, Professor Joachim Wittbrodt, told OT.

The team also discovered that a single gene, known as Atoh7, both triggers the cell division and the development of the cells within the cluster into the various retinal cell types.

Professor Joachim Wittbrodt explained: “The human genome contains the gene Atoh7 and there are several reports linking a loss or modulation of Atoh7 function to severe retinal abnormalities.”

The paper proposes that Atoh7 could one day be used to create new retinal cells to be transplanted into a patient’s eye, or to stimulate this process within the eye itself.

Professor Wittbrodt said that Atoh7 was well studied in mice. Alongside further work in fish, the team will conduct a study to see if boosting expression of the gene in mice will trigger nerve cell regeneration in their eyes, he highlighted.

“If yes, we will search for drugs with the potential to activate Atoh7.”

Professor Wittbrodt concluded: “We still have a long way to go before we can regenerate the human retina … But it is a goal to work towards – and it is not mere science fiction.”