When it comes to spectacular developments in medicine, the French ophthalmologist José-Alain Sahel has more to offer than many of his colleagues around the world who have been trying to treat the blind for decades. Sahel's appearances in Berlin were therefore awaited with particular suspense. This is also due to the fact that the researcher, who works at the University of Pittsburgh and the Eye Institute of the Sorbonne Université in Paris, uses two special high-tech processes: He combines sophisticated optogenetics with artificial visual prostheses. So genetic engineering and electronics.
Some time ago, Sahel reported on the treatment of the first patient in the journal Nature Medicine, and at the Falling Walls Conference he provided the spectacular pictures to go with it. His first lecture on the fourth floor of the Radialsystem was the prelude to the Charité symposium - an ideal opportunity to share the therapeutic progress of his procedure with colleagues such as Charité researcher and systems biologist Oliver Zeitz or Peter Hegemann from Humboldt University Exchange detail and depth. How important such encounters can ultimately become for an introduction to everyday medical practice was particularly evident here. Because even a research result published at the highest level leaves many questions unanswered. Uncertainties remain.This is why Sahel's approach to restore vision to patients who are blind from the genetic disease retinitis pigmentosa is still far from routine clinical practice.
But his experimental successes were more than suitable to impress the Falling Walls participants.
Retinitis pigmentosa is a disease that has long been studied by geneticists, and more than seventy different genes can be involved in its development.
Eyesight is always lost because the visual cells - the rods responsible for light-dark vision and the cones for color vision - gradually degenerate.
Without intact photoreceptor cells, however, the light falling on the retina does not produce any images in the head.
Not a cure but a silver lining
Optogenetics is a genetic engineering process that was first developed thirty years ago. Genes are provided with a kind of light switch and can therefore be regulated from the outside. It is crucial that the most important defective genes in retinitis patients are replaced in the photoreceptor cells and can always become active when light falls on the retina.
In the preclinical primate trials and the first nine patients that Sahel's group has treated so far, different optogenetic approaches were followed.
Sahel made it clear how long the successful genetic "repair" in the retina took because protein constructs and the vectors for the transfer of genes had to be optimized.
Again, this is an expression of how complex treating a single disease can be when the underlying genetic causes can be so diverse.
Another important instrument is the electronic glasses, a kind of camera eye that captures the images in front of the patient's head and projects them specifically onto the retina.