Zebrafish, hope for retinal regeneration?

Blindness, whether partial or total, affects millions of people worldwide. Current treatments primarily aim to slow the progression of retinal degeneration, without offering a cure. However, recent research on zebrafish offers new hope. This small tropical fish has a remarkable ability to spontaneously regenerate its retina after injury. Understanding the mechanisms at work could pave the way for innovative therapies to restore vision in humans.

Zebrafish: an exceptional model of regeneration

Zebrafish (Danio rerio) are widely used in biomedical research due to their embryonic transparency and rapid development. However, it is their ability to regenerate various tissues, including the retina, that fascinates scientists.

When an injury damages the zebrafish retina, Müller glial cells, normally dedicated to supporting neurons, dedifferentiate to become progenitor cells again. They then proliferate and differentiate into various retinal cell types, thus repairing the damage. This natural regeneration process does not exist in mammals, including humans, where retinal damage typically leads to irreversible vision loss.

Studies have shown that the neurotransmitter GABA (gamma-aminobutyric acid) plays a key role in this process . High concentrations of GABA inhibit the dedifferentiation of Müller cells, thus preventing regeneration. Conversely, a decrease in GABA promotes the transformation of Müller cells into progenitor cells, initiating the process of retinal regeneration.

Recent advances towards human application

Researchers have identified key factors involved in zebrafish retinal regeneration. Among them, the enzyme Kdm6b.1 plays a crucial role. This demethylase (an enzyme that acts like a chemical eraser by erasing small markers on DNA, which can reactivate certain genes) is present at high levels in regenerating tissues and is essential for activating the genes necessary for regeneration. Without this enzyme, zebrafish are unable to regenerate their retinas.

By identifying and understanding these mechanisms, scientists hope to stimulate similar processes in humans. Experiments on mice have shown that a small repair power of the eye can be awakened by stimulating certain internal mechanisms. While these results are still far from clinical application, they suggest that retinal regeneration in humans is not out of reach.

A revolution on the horizon or a scientific utopia?

Although the road is long, this research opens a new chapter in the treatment of retinal diseases: AMD , retinitis pigmentosa, or even traumatic lesions. By one day making it possible to "wake up" our own glial cells, we could consider not only slowing down degeneration, but restoring vision.

For eye care professionals, these scientific advances offer hope. They could ultimately transform the care of patients with retinal degeneration or other conditions that lead to blindness. In the meantime, it is essential for professionals to stay informed of research advances in order to best advise their patients and collaborate effectively with ophthalmologists and other specialists.

Zebrafish, with their natural capacity for regeneration, offer a valuable source of inspiration for ophthalmology research. Although many challenges remain before these discoveries can be applied to humans, recent advances suggest the possibility of restoring vision in patients currently considered incurable. For eye care professionals, these prospects reinforce the importance of their role in the vision care chain and underscore the need for constant scientific monitoring.