Researchers have been working on bringing about a moment in the years ahead when we will be capable of growing “an eye in a dish” and transplanting it to restore eyesight to someone who is blind, and it is not as far away as you may imagine.
It’s essential to consider how eyes develop naturally so that we can attempt to reproduce them in the lab. We’ve discovered a number of critical genes that, when they’re defective, have a significant impact on eye development.
Some genetic abnormalities, for example, cause anophthalmia (one or no eyes) or microphthalmia (abnormally small eyes), while others cause cell-specific problems such as the deletion of rods or cones at the back of the eye.
Developing an Eye in a Dish
As you might expect, the genes that govern where an eye originates, how big it will be, the cell types that will develop within it, and the function of those cells are all carefully regulated. The secret is to turn them on in the correct location, at the correct time, and in the correct order. Transcription factors, which are regulatory proteins, are in charge of this.
All transcription factors, as well as the genes they control, are encoded in our DNA. DNA is essentially a developing human’s guidebook, which is bundled into the single cell that develops when sperm fertilises an egg.
These cells are considered pluripotent rather than omnipotent because they can only grow into an embryo (not a placenta or amniotic sac). The pluripotent cells of the inner cell mass are referred to as human embryonic stem cells (hESCs).
The fact that hESCs could be cultivated in the lab to grow into 3D eye-like structures simply by adding particular nutrients and growth agents to the culture media was a huge scientific breakthrough. It appears that once the hESCs were placed on this developmental pathway, they were able to self-organize into the formation of an eye without the use of transcription factors.
Another discovery came when scientists discovered that fully differentiated cells, such as skin cells, may be reprogrammed to become “induced” pluripotent stem cells by going back in time (iPSCs). All that appears to be required is the forced production of four transcription factors that are generally exclusively found in stem cells in skin cells.
This discovery made it possible to reprogramme cells from a patient’s skin biopsy into iPSCs, allowing them to be cultivated into eye tissues in the lab using the patient’s own cells rather than hESCs.
There are still numerous obstacles to overcome before lab-grown eyes may be used for transplantation. The retina comprises a complex circuitry made up of nerve cells that is responsible for converting visual data into perceptible images.
Transplanting an eye or individual cells from one eye into another and expecting them to connect flawlessly with all of the nerves necessary for normal vision is not straightforward.
So far, the results are encouraging, and RPE cell transplantation appears to be a safe procedure. Therefore, it’s not too far away when we may be able to grow “an eye in a dish” and transplant it to restore a blind person’s vision!