Donor organ’s blood type altered for the first time
In a world first, researchers at the University of British Columbia (UBC) in Canada have successfully transplanted a human donor kidney that they artificially swapped from someone with type A blood into a universal type O kidney. This breakthrough could pave the way for creating a universal blood supply, as well as the ability to achieve similar results with other vital organs.
The riskiest and often most difficult part of an organ transplant procedure is the distinct possibility that the patient’s body will reject the organ itself. The culprit is often your overly skeptical immune system, which can attack a graft as if it were a foreign object. The risk of rejection can be offset by carefully matching the molecular similarities between a donor and patient and ensuring that the patient is on a regimen of immunosuppressants. However, current treatments are far from perfect. It is estimated that 15 to 20 percent of all kidney transplant recipients will face the consequences of organ rejection.
These rates could start to drop thanks to a groundbreaking trial detailed recently in the journal Natural biomedical engineeringThe assay is the culmination of more than a decade of work and relies on specially designed enzymes grown in the laboratory.
Antigens have long been one of the main problems in organ donation. These sugars that line the blood vessels of organs help determine a person’s blood type. At the slightest sign of a problem, the transplant recipient’s immune system goes into attack mode. This is why complications can arise even when a person with blood type A receives an organ of the same blood type. However, type O blood is considered universal and can be administered to a larger number of recipients. For this reason, donor networks are often strained, since more than half of the waiting lists for kidney transplants are made up of type O patients.
To avoid the worst consequences, the current preparation to avoid graft incompatibility involves eliminating antibodies using powerful immunosuppressants. Additionally, organs must come from living donors as quickly as possible. However, in 2019, pathologists discovered a pair of enzymes that dissolve sugars defining type A blood. Once eliminated, the blood functionally became type O.
“These enzymes are very active, very selective, and work at very low concentrations. This made the whole concept feasible,” study co-author Jayachandran Kizhakkedathu said in a statement.
A few more years of analysis and experimentation pushed the capabilities of the technique further. In 2022, collaborators successfully converted the blood type of the lungs and kidneys outside the body. From there, it was a matter of confirming that the process could be replicated in a living human patient.
The answer came in 2023, thanks in part to the family of a patient suffering from a complete loss of brain function. After learning about recent research, the person’s loved ones agreed to attempt a kidney transplant with enzyme modification into the person’s body.
âIt worked like a charm,â Kizhakkedathu recalls after reviewing the data. “I was so thrilled. It was a dream moment.”
For about two days, the kidney functioned without any evidence of hyperacute rejection. This type of rejection is the most intense adverse outcome and can destroy a rejected organ within minutes. On the third day, a few type A blood markers resurfaced and caused a mild reaction. Despite this, the organ suffered far less damage than a normal imbalance, and the team even documented indications that the body was learning to accept the organ.
“This is the first time we’ve seen this play out in a human model. It gives us invaluable insight into how to improve long-term outcomes,” Withers explained.
If the team receives approval for clinical trials, they will then work to develop these enzymes, first to create universal donor blood, as well as to apply the advances to other organs.
âThis is what it looks like when years of basic science are finally connected to patient care,â Withers said.
Shop Amazon’s Prime Day Sale
