Scientists at Université de Montréal have successfully transplanted retinas made from stem cells into blind mini-pigs – and, it seems, made them see again, according to a new study.
Published today in the British biological journal Development, the research led UdeM neurosciences professor Gilbert Bernier shows potential for treating retinal degenerative diseases in humans, as well.
“To get as close as possible to human clinical application, we chose mini-pigs because the size of their eyes is near that of humans and the animals are about the same weight as humans,” said Bernier.
“Hence, all surgeries in our study could be performed by a retinal surgeon.”
In their stem cell and developmental biology laboratory of the UdeM-affilated Maisonneuve-Rosemont Hospital, Bernier and his team developed a method to coax stem cells into forming sheets of cells that recapitulate the structure of the human retina.
The type of stem cells they used are called human induced pluripotent stem cells – immature cells ‘reprogrammed’ from an adult (mature) cell that can differentiate into any type of cells in the body. Using the stem cells, the researchers made ‘retinal sheets’ that are enriched in immature versions of the cone photoreceptor cells, which could become mature cone cells when cultured in the lab.
After successfully creating the retinal sheets in a dish, the researchers tackled the next challenge: transplanting these sheets into mini-pigs with damaged macula. Once that was done, they found that the retinal grafts were able to integrate into the mini-pig’s damaged retinal tissue.
The mini-pigs showed signs of restored vision: new neural connections were formed between the grafted photoreceptor cells and the minipigs’ neural cells, and the scientists could detect neural activity of the photoreceptors at the grafted area when the mini-pigs were placed in a well-lit room.
