Since the discovery of induced pluripotency more than a decade ago, researchers have been working towards the use of this technology to produce cells for use in tissue engineering and regenerative therapies. Induced pluripotent stem cells are functionally equivalent to embryonic stem cells; given suitable recipes and methods for the surrounding environment and signals, they can be made to generate any of the cell types in the body. The cornea of the eye is a comparatively simple starting point for tissue engineering, easier to work with in many ways, in generating tissues and in delivering cells to the patient. Here, the first repair of a human cornea is reported, using tissue structures produced from induced pluripotent stem cells.
A Japanese woman in her forties has become the first person in the world to have her cornea repaired using reprogrammed stem cells. The woman has a disease in which the stem cells that repair the cornea, a transparent layer that covers and protects the eye, are lost. The condition makes vision blurry and can lead to blindness. To treat the woman, researchers created sheets of corneal cells from induced pluripotent stem (iPS) cells. These are made by reprogramming adult skin cells from a donor into an embryonic-like state from which they can transform into other cell types, such as corneal cells.
The woman's cornea remained clear and her vision had improved since the transplant a month ago. Currently people with damaged or diseased corneas are generally treated using tissue from donors who have died, but there is a long waiting list for such tissue in Japan. Japan has been ahead of the curve in approving the clinical use of iPS cells, which were discovered by stem-cell biologist Shinya Yamanaka. Japanese physicians have also used iPS cells to treat spinal cord injury, Parkinson's disease, and another eye disease. The Japanese health ministry gave permission to try the procedure on four people. The team is planning the next operation for later this year and hope to have the procedure in the clinic in five years.