Recently, a new study in Science Translational Medicine brings us one step closer to a universal transplant organ, according to the results of the experiment, the researchers achieved the conversion of donor organ blood type in an extracorporeal lung perfusion device
With the help of two enzymes, the lungs originally derived from blood donors of type A (hereinafter referred to as "type A lungs") have become type O lungs, which is expected to greatly improve the efficiency of organ transplantation
When it comes to organ transplants, it's easier to think of many patients lining up for the right organ, but in reality, there are also donated organs that may have to be discarded because there are no blood-compatible recipients nearby
And people with type O blood often face a higher risk of death because they have to wait longer for blood type problems
This is mainly because patients with type O blood contain anti-A and anti-B antibodies, which will reject donor organs of other blood types, so it is more difficult to obtain adapter organs
For example, patients who need a type O kidney transplant wait an average of 4-5 years on the waiting list, while those who need a type A kidney transplant only wait 2-3 years
If there was a way to remove blood group antigens from other blood group organs, those organs could become a universal transplant organ for all waiting patients
Marcelo Cypel, a professor of surgical medicine at the University of Toronto who has been working on universal transplant organs, has seen Stephen Withers, a professor of biochemistry at the University of British Columbia, use a set of enzymes to convert A and B red blood cells into O red blood cells
▲The extracorporeal perfusion system used in the study (Image source: Reference , credit: University Health Network)
The enzymes used in previous studies were all derived from the human gut bacteria, which feed on sugars similar to blood cell antigens.
Professor Withers believes that these enzymes could be the way to make universal blood
Cypel read the research, he immediately thought that the technology could be applied to organ transplantation.
He invited Prof.
Withers to collaborate, and the two hit it off
The research team first obtained some lungs that lost their value for transplantation, and used an extracorporeal lung perfusion device to keep the organs alive, mainly to maintain normal body temperature in the lungs, and to obtain nutrients, protein and oxygen through the device pump
In addition, the research will additionally use two enzymes, FpGalNAc deacetylase and Fp galactosaminidase, previously used by Prof.
Preliminary tests of the study found that exposure of type A lungs to these enzymes continuously for 4 hours eliminated 97% of type A antigens in the lungs
In the past, when performing lung transplantation, Professor Cypel kept the organ in the in vitro perfusion setting for 4-5 hours in advance, so the efficiency of these enzymes to clear the antigen is very practical in clinical practice
▲After adding enzymes to the perfusion system, most of the A antigens can be eliminated (Image source: Reference )
In addition, the research team conducted a safety assessment of these modalities, which were tested in type A lungs, where the right side of the lung was treated with enzymes and the left side served as a control
Four hours later, the study perfused the entire lung with type O plasma, and the lungs were recorded
The right lung still maintains intact vitality after being exposed to type O blood, while the left lung will soon experience hyperacute rejection, indicating that the anti-A antibodies in type O blood are causing extensive damage to organs
Of course, some questions still need further research to answer, such as whether the enzyme-treated type A lung will produce A antigen again after transplantation?
They are now preparing to test the real-world application and safety of such methods in clinical trials, and it is also necessary to demonstrate that the two enzymes used in the perfusion do not cause harm to the patient's body
Still, the research team is hopeful that the enzymatic treatment could be applied to all transplanted organs, not just the lungs
 Creating 'universal' transplant organs: New study moves us one step closer.
Retrieved Feb 18th, 2022 from https:// Creating universal blood-type organs for transplant.
Retrieved Feb 18th, 2022 from https://medicalxpress.
 Conversion of blood type A donor lungs into universal blood type lungs using ex vivo ABO enzymatic treatment, Science Translational Medicine (2022).