Japan's stem cell transplant improves vision in patients with corneal damage

A radical stem cell transplant conducted in Japan has significantly improved the blurred vision of three people with severe corneal damage. This clinical trial is considered a major breakthrough in stem cell research, being the first of its kind in the world.

Two years after the operation, no serious safety issues were reported, and it was observed that all three participants had a more transparent appearance to their corneas.

The study involved four participants with a condition called "limbal stem cell deficiency" (LSCD), which leads to the accumulation of scar tissue in the cornea.

The limbus, which supports the cornea while protecting the white part of the eye, is a region rich in stem cells that facilitates the regeneration of corneal cells. Loss of function in these stem cells can lead to vision loss over time. Currently, people with LSCD can receive a healthy corneal slice from one eye, but if both eyes are affected, a donor transplant is required.

Healthy blood cells were used Globally, only one in 70 of the 12.7 million people with corneal-related vision loss have the chance for a transplant. Even for those who can receive a transplant, there is a risk of tissue rejection.

This is where "induced pluripotent stem cells" (iPSCs) come in. These stem cells can be obtained from any human cell and reprogrammed into an embryonic-like state, allowing them to transform into the desired type of adult cell.

Last year, U.S. researchers announced that they had restored the vision of two patients with corneal damage using limbal stem cells. Now, scientists at Osaka University Hospital in Japan have taken it a step further by using iPSCs derived from healthy human blood cells, successfully restoring patients' vision.

Applications still experimental and potentially risky The iPSCs generated in the laboratory were transformed into corneal epithelial cell layers (iCEPS), which were transplanted onto the corneas with scar tissue removed, and covered with a protective contact lens. Within seven months of the transplant, all four patients showed improvements in vision. However, one year later, the vision of the 39-year-old patient with the most severe vision loss regressed again.

The best improvement in vision was observed in a 44-year-old woman and a 66-year-old man. Researchers suspect that in the third and fourth patients, an adverse immune response to the transplanted cells may have prevented the same improvement.

Although these small-scale trials are promising, such applications remain experimental and potentially risky. Researchers plan to conduct future multi-center clinical trials and build upon these encouraging results.