The finding from the University of Cambridge in the UK could increase the number of organs available in the future. The procedure would help people with minority blood groups.
Researchers at the University of Cambridge, in the United Kingdom, have achieved a scientific breakthrough for transplants. It involves altering the blood type of three donor kidneys. An advance that could increase the supply of kidneys available for transplant, especially in minority ethnic groups who are less likely to be a match for most donated kidneys.
For the procedure, they used a normothermic perfusion machine, which is a device that is attached to a human kidney to draw oxygenated blood through the organ in order to better preserve it for future use. Through that machine they circulated blood infused with an enzyme through the deceased kidney. The procedure was carried out by Professor Mike Nicholson and doctoral student Serena MacMillan.
The enzyme acted like “molecular scissors” to remove blood type markers that line the kidney’s blood vessels, thus turning the organ into the more common type O. That is, the enzyme removes the blood type markers that line the kidney’s blood vessels, effectively changing its blood type to type O. The process took a few hours when successfully performed on three donor kidneys.
Kidney transplant is one of the kidney function replacement treatments. It is indicated in cases of patients suffering from terminal (irreversible) chronic renal failure. They may receive a kidney from a deceased donor or from a related living donor.
At present, the kidney of a person with blood type A cannot be transplanted into another person with blood type B, nor vice versa. But changing the blood type to universal O – like the one being developed by the Cambridge researchers – would allow more transplants to be carried out. Because the universal type O can be used for people of any blood type.
Following the results of the research, MacMillan said: “Our confidence was really boosted after applying the enzyme to a piece of human kidney tissue and quickly seeing that the antigens were removed. After this, we knew the process was feasible and we just had to scale up the project to apply the enzyme to full-size human kidneys.”
Taking human type B kidneys and pumping the enzyme through the organ using our normothermic perfusion machine, “we saw that in a matter of a few hours we had converted a type B kidney to a type O,” he explained. “It’s very exciting to think about how this could potentially impact so many lives,” she acknowledged.
People from minority ethnic groups typically wait a year longer for a transplant than white patients, so the study could have particular implications for them, experts say. People from minority communities are more likely to have type B blood and with the low donation rates of these populations there are not enough kidneys to go around.
In 2020 and 2021, just over 9% of all UK organ donations came from black and minority ethnic donors. But black and minority ethnic patients make up 33% of the waiting list for kidney transplants. Now the researchers need to see how the newly switched type O kidney will react with a patient’s usual blood type in their normal blood supply.
The machine allows them to do this before testing people, as they can take kidneys that have been switched to type O, and put in different blood types to control how the kidney might react.
Research leader Mike Nicholson commented: “One of the biggest restrictions on who can transplant a donated kidney is the fact that it has to be a blood type match. The reason is that you have antigens and markers on your cells that can be A or B. Your body naturally produces antibodies against those that you don’t have. Blood group classification is also determined by ethnicity, and minority ethnic groups are more likely to have the rarer type B.”
Meanwhile, Dr. Aisling McMahon, executive director of research at Kidney Research UK, said the preliminary results of the research could be “game-changing”. After testing the reintroduction of other blood types, the team will study how the method could be used in a clinical setting. The research, funded by the charity Kidney Research UK, will be published in the British Journal of Surgery in the coming months.
Last June, a worldwide epidemiological study on the situation of kidney transplants had been published. Data was collected from 155 countries. Kidney transplantation was available in 74% of these countries, with an average incidence of 14 per million inhabitants. Transplant accessibility varied greatly; even in high-income countries, it was disproportionately lower for ethnic minorities.
Universal health coverage of all transplant treatment costs was available in 31% of countries, and 57% had a transplant registry. The research was published in the journal Transplantation.
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