Fish may point way to blindness treatment

Wednesday August 1 2007

Zebrafish, which have the ability to repair damaged and diseased cells in their own eyes, could help find a cure for blindness, the Daily Mail and other newspapers reported.

The Daily Mail , The Sun and The Scotsman reported that the stem cells which heal the retina in the eyes of zebrafish, are present in the human eye but do not appear to be active.

They story was based on a study in which researchers grew the stem cells in a lab and then transplanted them into rats with diseased retinas. The Scotsman reported that “in future, these cells could be injected into the eye as a treatment for diseases such as macular degeneration, glaucoma and diabetes-related blindness”.

The study shows that cells obtained from human eyes can be grown in a laboratory setting and transplanted into rat eyes, where they express known markers of neural retina cells.

Though the study seems to be well conducted, care is needed in using animal studies to describe how humans might benefit. We need to wait for human studies before drawing definitive conclusions, but the potential of this technology is exciting.

Where did the story come from?

The research was conducted by Jean Lawrence and colleagues at Moorfields Eye Hospital in London and University of Washington, Seattle, US, and  published in the peer-reviewed journal, Stem Cells .

What kind of scientific study was this?

This was a laboratory study using cultured Muller glial cells; a type of cell in the retina which can take on some of the characteristics of stem cells and work towards repairing damage. The cells were obtained from the neural retina of human eyes, marked with a protein to keep track of them, and then transplanted into rat eyes. The rat eyes were removed and frozen sections examined to investigate the activity of the transplanted Muller cells.

What were the results of the study?

The human eye cells were successfully grown in the laboratory under normal culture conditions, and exhibited characteristics of Muller glial and stem cells. After adding substances known to help stem cells transform into different types of cells, some of the cells acquired the structure and characteristics of neural retinal cells. After transplanting the cells into the subretinal space in rat eyes, the cells were found to migrate into the retina and behave similarly to retinal neuron cells.

What interpretations did the researchers draw from these results?

The researchers concluded that this indicates that neural retinas in adult humans contain a population of cells that display the characteristics of both Muller glial and stem cells and propose that the cells “may have potential use for cell-based therapies to restore retinal function”.

What does the NHS Knowledge Service make of this study?

This research appears to be a good laboratory study, using quite complicated methods.

The study investigates the cells in a laboratory setting and within rats, and the cells have not been tested in human eyes. Therefore, it is not clear how these cells would behave if transplanted into human eyes.

We will only be able to draw definitive conclusions about the potential of these cells when more animal and human studies have been done. Any potential treatment for blindness may take several years to develop.

Analysis by Bazian
Edited by NHS Choices