Donor transplantation with “converted” organs could radically transform medical world

Thousands of people die every day because there are not enough donor organs available for all those waiting for a transplant. While the main cause of this shortage is the low overall rate of organ donations to begin with, another key challenge lies in finding a compatible donor for each recipient. Many biological factors must align for a transplant to proceed — one of the most critical being blood type. In a significant step toward expanding access to donor organs, scientists have successfully converted a donor kidney from one blood type to another and performed a transplantation.

The kidney originally came from a blood-type-A donor but was converted to blood type O, effectively making it a “universal” transplant. Although the organ functioned well for two days after being transplanted into a brain-dead patient before showing signs of rejection, an article from Live Science reports that the approach could “pave the way for shorter waits on organ donor lists.”

Humans have four major blood groups — A, B, AB, and O — and the immune system of a person with one type can react strongly against another. For instance, a type-O transplant candidate can only receive a type-O kidney, while people with A, B, or AB blood can also receive type-O organs. Each blood type is defined by immune-triggering molecules called antigens. Since O blood lacks these antigens, it can be accepted universally, while organs from other blood types can trigger rejection in a type-O recipient.

In the late 1980s, scientists developed a way to transplant ABO-incompatible (ABOi) organs — meaning an organ from a donor with one blood type into a recipient with another. However, this procedure is complex and can take several days. In 2022, researchers made a breakthrough by developing an enzyme-based treatment that can convert an organ into a “universal” transplant, known as enzyme-converted O (ECO).

Latest study paves the way for groundbreaking changes

The latest research, published this week in Nature Biomedical Engineering, explains the science behind this process in detail. “The ECO process has been demonstrated for lungs,” said study co-author Stephen Withers, professor emeritus of biochemistry at the Canadian University of British Columbia, in an email to Live Science. “We hope it works for all other organs — it should!”

Withers had previously been part of the 2022 team that converted lungs from type A to type O, though those organs were never transplanted into a human. In the new study, he and his colleagues used a type-A kidney that had been deemed unsuitable for transplant and successfully converted it to type O by perfusing it — or flushing it — with a special enzyme solution, a process that took roughly two hours.

“Perfusion devices and organ preservation solutions are quite commonly used to keep organs in good condition between donation and transplantation,” Withers explained. To achieve the conversion, the team added specific enzymes into the perfusion fluid that removed blood-group antigens, preventing immune rejection.

“In this way, organs will not then get recognized and targeted by the anti-A antibodies present in the blood stream of the recipient,” Withers said. While the procedure does not permanently eliminate problematic antigens, it may help reduce the immune system’s immediate reaction and extend the organ’s viability after transplantation.

Although the ECO kidney transplant marks a milestone in transplant medicine, the researchers caution that the method is still in its early stages. Nonetheless, Withers remains optimistic, expressing confidence that the enzyme-conversion technique could one day be applied widely to make organ transplants faster, safer, and more accessible.

By Nazrin Sadigova