The manipulation of proteins in cells inside the body using light is called optogenetic therapy and was first developed in the early 2000s. Its development resulted in several significant discoveries about the inner working of the human brain and was actively researched in animals. Since most of the research using the technique was focused on animal trials, functional improvement using optogenetic therapy was never reported in humans.
Improvement in humans has now been reported in a new paper published by a group of scientists from the University of Pittsburgh and other institutions around the world. The study describes the first time a patient has achieved partial functional recovery from a neurodegenerative disease using optogenetic treatments. In this case, a blind patient partially recovered their vision after treatment.
José-Alain Sahel, director of the UMPC Eye Center at the University of Pittsburg and professor at Sorbonne University in France, says the paper is the cumulation of more than 12 years of work. The paper focuses on a patient in Paris who was diagnosed with retinitis pigmentosa 40 years ago. Retinitis pigmentosa is a neurodegenerative disease that destroys light-sensitive cells in the retina, leading to complete blindness.
The condition is caused by mutations in more than 71 different genes making gene therapies to replace proteins to repair the condition challenging and not particularly effective. The researchers tried to treat the condition from a different angle that didn’t rely on trying to fix mutated genes in cells that respond to light. Instead, they tried to activate nerve cells directly using optogenetic therapy.
In the study, the researchers injected the patient’s eye with worse vision with an adenovirus-associated vector that carries genetic information, including a light-sensing protein called ChrimsonR. That particular protein comes from a glowing algae and is found in nature. The flow of ions activated the cells and causes them to fire and transmit the signal through nerve endings to the brain. The team used special goggles featuring a camera that detects changes in light intensity pixel by pixel as distinct events to activate the ganglion cells.
Researchers say that after a period of adjusting and learning how to use the technology, the results were remarkable. The patient could locate, identify, and count different objects using the treated eye while wearing the goggles. The patient could not visually detect any objects before the injection or without the goggles after the injection.