The scarcity of organs highlights the importance of continuing to work with xenotransplantation

“What we did on September 25, 2021, was we took an organ from a genetically modified pig and implanted it into a person who had recently died, was declared brain dead, and the family decided to donate their body to participate in the study. The objective was to provide the first evidence of what appear to be promising results in non-human primate organs and that could be translated into good hope in humans”, said Dr. Robert Montgomery, director of the New York University Langone Transplant Institute. He became the first surgeon to successfully transplant a pig kidney into a living person.

Biomedical advances have promoted this practice of xenotransplantation, which consists of implanting organs from animals with high genetic compatibility with humans. Although the attempts and experimental phases have their origin at the beginning of the 20th century, the chances of achieving a successful surgery that increases the patient’s life have now increased.

On the occasion of his visit to Mexico, El Economista had the opportunity to chat with Dr. Montgomeryconsidered a world leader in kidney transplantation and an authority on xenotransplantation, is himself a heart transplant patient and shares his position on this innovative alternative and future challenges.

“I participated in my own clinical trial and received my heart from a drug overdose victim who had hepatitis C and had the same disease, then took the antiviral drug and was totally cured, after this I have spent much of my career trying to expand the opportunity for people who receive the miracle of transplantation , but the truth is that with the increase in cases that need it, we are not able to cover the need and that is constantly increasing, it is exponential.”

Only in Mexico, according to the National Transplant Center (Cenatra), more than 17,000 people are waiting for a kidney transplant; 5,259 corneas, 238 liver and 54 heart. In contrast, despite the fact that the waiting list exceeds 23,000 patients, only 7,000 transplants were performed in the country last year, that is, less than a third of those required.

Following Montgomery’s feat, on January 7, David Bennett, a 57-year-old man with terminal heart disease, received a genetically modified pig heart at the University of Maryland Medical Center. The first heart transplant from a pig to a human who lived for two months, Montgomery He considers it successful but short, because there was brain death and the patient was kept on a ventilator, so at some point a closure had to be made with the family. But he says this answered some very interesting questions, and other groups are doing similar research.

“It’s been very exciting and the world is wondering what’s next, what can we expect from this?”

Challenges of xenotransplantation

The doctor montgomery explains that for now we’re stuck in the paradigm of what it means for someone to have to die for someone else to live, “and when you think about that and the ever-increasing need for organs for transplant, that paradigm doesn’t seem like it’s going to work.” function”. He said what we need is a sustainable, renewable source of organs “and that’s what xenotransplantation could give us.”

“With the current paradigm of only having a source of organs from people who have died or living donors, it was very clear to me, as I got sick and realized that I have a genetic heart problem that it has affected many members of my family, in addition to being very ill before qualifying for a transplant, and that the shortage of organs continues to be our great challenge, since barely half of the people who require a transplant enter only one list While others are dying, I knew we needed a change, a new source of organs.”

“I always felt that there is some reason or purpose why I am still here, and I don’t know, maybe this is the reason,” says the doctor.

The specialist considers that the most promising sources of renewable and sustainable organs is the xenotransplantation using organs from other species or bioartificial ones, where an organ is built, but with the other alternative, the organ is already made, the challenge is to prevent the immune system from eliminating it; It also seeks to safeguard infections between species, “we have already been through this pandemic and obviously we are concerned about zoonoses and the possibility of an infection between species.”

He said that for more than 30 years they have been working with genetic engineering, especially with pigs and primates, however the latter are very difficult species that, although they are genetically closer to humans, are very fragile and it is more likely that there could be a transmission of some disease such as HIV, they tend to have infections and finally, the public perception of using primates as a source of organs is not good, they are also increasingly scarce worldwide.

For their part, the pigs have undergone genetic modification and have been bred so that they all have the type O+ blood type and can be used for any recipient, they are bred to reduce the risks of zoonoses and the public perception is better, because it is even a source of food for humans.

Regarding the future, he explains that we could say that we are in an initial phase “and we know that it is not like making a new molecule or a drug, it is much more complex, but let’s think about our cell phones, just ten years ago we could not do everything that we now solve with them, I do not see why xenotransplantation could not follow this type of trajectory”.

He concludes that, although a human organ will be preferable, in many cases there is no option, and people who need a transplant become invisible, “we have to be aware of this and how well these first steps are being achieved, in the future this option could be more affordable even than a human organ”.

“We could have stayed in the step of continuing to do genetic modifications or more studies in primates, going from a monkey to a living human was a big jump, we took an intermediate jump, which was to test first in a recently dead human to be sure that there wasn’t a catastrophic event and it harmed a living human. This gave us confidence, both doctors and regulatory organizations, to be able to move forward and go to a phase I trial.”

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