Scientists Treat Severe Injuries in One Eye With Stem Cells From the Other

Patients’ own stem cells could help them recover from chemical burns that damaged a single eye, a small, preliminary study suggests

A close up of a person's eye, with their nose and eyebrow visible
Researchers took stem cells from the healthy eyes of patients who had suffered a chemical burn in their other eye. They then transplanted the stem cells into the injured eye. Veronique Beranger via Getty Images

With a groundbreaking, experimental surgery, scientists have treated four patients with extreme injuries in one eye by transplanting stem cells from each individual’s healthy eye.

“Case-by-case reports of those four patients have shown an improvement in quite a few parameters and definitely a decrease in their pain and symptoms,” Ula Jurkunas, an ophthalmologist at Massachusetts Eye and Ear and first author of the new study, tells Science Friday’s Ira Flatow in a radio interview.

For example, Phil Durst, one of the study participants, had suffered a chemical burn and was “completely blind with debilitating headaches” prior to the procedure, he tells Laura Ungar of the Associated Press (AP). Now, however, he sees well enough to drive.

While the small, preliminary study didn’t seek to quantify how effective the treatment was, it demonstrated the procedure is possible, without any known immediate dangers, the researchers reported last week in the journal Science. A larger, longer-term trial is currently studying the effectiveness of this treatment.

“I think that we showed that it is feasible to employ [the] body’s own stem cells and to grow them and to place them back in a patient, and it’s also safe,” Jurkunas says to Science Friday of the preliminary study. “The efficacy data is the next step for us to show.”

The new treatment is meant to help people with limbal stem cell deficiency, an eye condition that can result in pain, blindness and a thinning of the cornea, or the eye’s transparent outer tissue. It occurs when stem cells in the limbus—a part of the eye around the cornea—fail to repair and regrow the cornea’s surface after an injury, such as from chemical burns, radiation or toxins, according to Columbia University.

Eye injuries can sometimes be treated with cornea transplants, but if patients have limbal stem cell deficiency, a cornea transplant won’t work.

Currently, other kinds of limbal stem cell transplants come with drawbacks—they involve either a large biopsy from a patient’s healthy eye, which can put that eye at risk, or they require donor cells, which the recipient’s eye can reject, Jurkunas tells Time’s Jamie Ducharme.

In the new study, the researchers took a small biopsy from the limbus of each patient’s healthy eye, then separated the stem cells from the rest of the biopsied tissue. They then grew the stem cells in a lab for a couple of weeks before transplanting them into the patient’s injured eye, per the AP.

The trial enrolled five patients, and four of them received transplants. The other participant’s biopsied cells did not grow successfully in the lab, so their treatment could not be completed. The researchers followed the four transplant recipients for 12 months. Vision improved for two of these patients following the procedure, and for the two others, the operation prepared them for a cornea transplant.

The research is “a really exciting” proof of concept, Julie Schallhorn, an ophthalmologist at the University of California, San Francisco, who was not involved in the study, tells NBC News’ Theresa Tamkins, Jessica Klingbaum and Kristen Dahlgren.

“It’s a very, very difficult-to-treat condition,” she says to the publication. “There are really not any good solutions for it right now.”

Around 1,000 people each year in the U.S. have damage in one eye but can’t receive a cornea transplant, Jurkunas tells Time. However, since the experimental treatment involves taking stem cells from a healthy eye, it wouldn’t work for people who have suffered damage to both eyes.

The next phase of the research will follow participants for 18 months and include 15 patients, per the AP.

This new treatment is “very promising, and hopefully, if successful, it would be a good option for complicated cases,” Sezen Karakus, an ophthalmologist at the Johns Hopkins University School of Medicine who did not contribute to the findings, tells NBC News.

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