Gibraltar Barbary Macaque. Image: RedCoat by CC BY-SA 2.5 via Commons

Scientists have successfully grafted eye tissue into monkeys and it survived, thrived and shows signs that it could actually pass information to become a functioning.  This could pave the way for new hope for those with currently untreatable genetic eye disease.  While this success does not mean that a cure is imminent, it does demonstrate the feasibility of such a procedure as a method of future treatment.  Growing eye tissue in a lab for the purpose of implanting it certainly will get a lot of focus moving forward.

Gibraltar Barbary Macaque
Gibraltar Barbary Macaque. Image: RedCoat by CC BY-SA 2.5 via Commons

Retinitis pigmentosa (RP) is the focus of this study which is actually a group of genetic conditions where the retina degrades over time.  The retina are the light sensitive parts of the eye.  RP rarely leads to total blindness, those affected progressively lose their peripheral vision and struggle to see in low light situations.

There have been more than 45 genes linked to RP, signaling scientist to consider gene therapy as a potential solution in their research.  This gene therapy is among several treatment strategies being researched but improvements in cell culture techniques has lead to the idea of replacing damaged cells with those grown in a lab from stem cells.  It has already been demonstrated that it is possible to grow enough retinal tissue using human stem cells.  Studies on rodents have proven that transplanted tissue can  survive in the eye and even integrate with the host cells.

Because of their physiological and anatomical differences from humans, rodents can only give us a glimpse of what could be possible.  Because of these difference scientist turned to a more similar study animal to continue to develop the technique and produce more reliable and viable data.  That is where this current study comes in. replacing rodents with primates.

Researches in Japan began by growing retinal tissue from human stem cells, then transplanted them into rats that either did or did not have degenerated retinas.  The excitement began when the tissue matured in the rodents, forming layers of photoreceptor cells.  This process was repeated in primate models with RP.  You can read their account in the journal Proceedings of the National Academy of Sciences.

The excitement grew when the transplanted tissue not only survived but actually turned into both types of photoreceptors, cones and rods.  But the  most exciting part is that the tissue actually showed signs of integrating with the bipolar cells.  Bipolar cells are sensory nerves that relay visual information to the brain.

Now that scientist have established a model that has potential to work then can further develop the technique to hopefully develop a way to restore full-functioning sight to humans that are affected by RP.  There is much to be hopeful and encouraged by with these successful grafts.