Breakthrough: Stem Cell Transplant Restores Vision for Multiple Patients

A groundbreaking stem cell transplant has greatly improved the blurred vision of three individuals with severe corneal damage.

This clinical trial, conducted in Japan, marks a world-first and a major milestone in stem cell research.

Two years post-operation, no major safety issues have emerged, and all three treated corneas appear notably clearer.

The study included four participants, each affected by limbal stem cell deficiency (LSCD), a condition that leads to scarring on the cornea.

The Cornea’s Essential Frame

If the cornea is viewed as the eye’s “transparent window,” then the limbus serves as its frame, holding it in place against the sclera, or white part of the eye.

This essential frame contains a rich supply of stem cells, which act like tiny windshield wipers, replenishing damaged cells to keep the cornea clear as we age.

Without this stem cell maintenance, gradual vision loss becomes inevitable.

When One Eye Is Affected vs. Both

Currently, people with LSCD in one eye can have scar tissue removed and replaced with healthy corneal tissue from their other eye. However, when both eyes are affected, a donor transplant is required.

Of the 12.7 million people worldwide with corneal vision loss, only 1 in 70 can access a transplant. Even for those who do, survival of the graft is often an issue due to the risk of rejection.

This is where induced pluripotent stem cells (iPSCs) offer promise.

iPSCs, created by reprogramming any human cell back to an embryonic-like state, can replicate indefinitely and transform into any adult cell type, including corneal cells.

In 2023, U.S. researchers restored vision in two patients with corneal damage using limbic stem cells within a year of treatment.

Now, scientists at Osaka University Hospital in Japan have advanced this work, using iPSCs derived from healthy blood cells to restore vision.

In the lab, these iPSCs were developed into corneal epithelial cell sheets (iCEPS), which were then transplanted over patients’ corneas after scar tissue removal, with a protective contact lens placed on top.

Seven months after the transplant, all four patients experienced improved vision. However, a year later, the vision of patient 4, a 39-year-old woman with the most severe vision impairment, had deteriorated again.

Patients 1 and 2—a 44-year-old woman and a 66-year-old man—showed the most significant and lasting improvements.

Potential Immune Response in Patients 3 and 4

Researchers believe that patients 3 and 4 may not have experienced the same improvements due to an underlying immune response to the transplant. Apart from steroids, none of the patients were given immunosuppressive drugs.

Previously, scientists used iPSCs from a patient’s own skin to restore vision for those with macular degeneration—damage to the retina’s center—but this marks the first time such an approach has succeeded in treating this particular type of vision loss without using cells from the patients themselves.

While these small trials are promising, such procedures are still highly experimental and carry potential risks. Much more research is needed to evaluate their safety and effectiveness.

“To our knowledge, this study provides the first description of iPSC-derived cell constructs transplanted onto patients’ corneas, offering a promising future treatment option for individuals with LSCD,” the Osaka University Hospital team notes.

To conclude, they are now preparing a multicenter clinical trial to “build on the encouraging results.”

Read the original article on: Science Alert

Read more: Blinking Can Enhance Your Vision, Unnoticed Until Now