Very soon, sooner than we could imagine, the more than 7,000 people waiting for a transplant in Argentina (mainly kidneys, with more than 5,000 cases) will be able to receive an organ to treat themselves.
But this organ is not going to come from another human, but from pigs. This is the future of human transplants which, in the world and also in Argentina, are advancing by leaps and bounds.
German scientists announced last week that they plan to clone and then breed genetically modified pigs this year to serve as donor hearts for humans, based on a simpler version of an animal engineered in the States. States which was used in the first transplant last month. from the pig to the man of the world.
In the first such surgery, a team from the University of Maryland Medicine last month transplanted 10 modified pig hearts into a terminally ill man. His doctors say he is doing well, although risks of infection, organ rejection or high blood pressure remain.
The medical prowess achieved opens the doors so that very soon animal-to-human transplants or xenotransplantation can be carried out periodically.
In Argentina, the Single Central National Coordinating Institute for Ablation and Implantation (INCUCAI) is the body that promotes, standardizes, coordinates and supervises the activities of donation and transplantation of organs, tissues and cells . And on its website, it records more than nearly 7,000 organ orders as of yesterday.
However, each year only about 1,200 to 1,500 people are transplanted in the country. That is to say, organs are missing. In the United States, about 107,000 people are waiting for an organ transplant and 90,000 need a kidney, according to the United Network for Organ Sharing. And the average wait times for a kidney are three to five years.
Xenotransplantations (from the Greek xenos, which means strange, foreign) are organ transplants between different species, for example between pigs and humans. They were proposed more than 30 years ago to compensate for the lack of organs required by people on waiting lists.
“Using animals to provide organs to humans is an old idea, and what it seeks is to find a donor that is compatible with as many individuals as possible,” said Dr. Rafael Fernández-Martín , professor of the chair of animal physiology at the university. Faculty of Agronomy of the University of Buenos Aires (UBA), which is working with his colleague Dr. Daniel Salamone to produce in the near future organs suitable for the transplantation of genetically modified pigs and thus improve the quality of life of patients waiting for a compatible human donor.
So far, the main obstacle has been that “the immune system seeks to identify foreign cells in the body, which are differentiated by the different glycosylations ─a biochemical process in which sugars are added to molecules─, and during detecting a foreign organ, it destroys it within minutes,” he explained.
Talking about how his concern for reaching a universal donor began, Salamone returned to the 1990s, when Dr. René Favaloro spoke of the need to overcome the so-called “hyperacute rejection” exerted by the immune system after a transplant by not recognizing the new organ as part of the body.
Adrián Abalovich, researcher and professor at the School of Science and Technology (ECyT) of the University of San Martín (UNSAM) explained today on Miter radio that in addition to the historic lung transplant, there is already a successful history of kidney transplants. “The three kidney transplant operations performed involved brain-dead people. It was for a few hours. And if the natural rejection could be avoided thanks to the preliminary genetic modification of the pigs. Xenotransplantation opens up enormous expectations for the future,” said the specialist, who hopes that in two years these transplants will be able to be performed in the country. The expert said that there are 130,000 people waiting for transplant every year worldwide and only 10% of operations are performed due to organ shortage.
“In our country, there is also a great need. Because in addition to the more than 7,000 people waiting for a transplant, there are still 30,000 people on dialysis, who are not on the waiting list, because admission is very demanding. But if we could advance in this type of pig transplant, they could be included, modifying their quality and life expectancy, “added the specialist who participated in a study in the country that allowed to transplant pancreatic islets of pig in the bodies of patients with diabetes. 1, to reactivate your insulin production. It is the largest clinical trial in the world and it was developed at the Eva Perón Hospital in San Martín.
Making a pig’s organ look like a human organ is no easy task. Among the multiple factors involved in rejection are the galactose residues in pork and to which our body responds automatically. For this reason, they point out, xenotransplantation is an idea for the future with results still in the experimental phase, far from being clinical. However, progress in gene editing using the CRISPR technique is encouraging. Fernández-Martín highlighted its “ease of handling and its specificity”. And he added: “I like to compare CRISPR to a computer tool that allows you to locate a citation from a book not just in one issue, but throughout the National Library.”
About CRISPR, which was discovered from the primitive immune system of bacteria, Salamone simplified: “It basically works through two components, an enzyme that has the ability to cut DNA and a small RNA (ribonucleic acid) with the ability to bind to the enzyme and tell it where to cut in a specific sequence in which we want to act”.
“So these are real genetic scissors with which you can cut in specific places. Add to that our proven ability to insert precise footage into such spaces. Among the associated applications, for example, hypoallergenic milks or the improvement of meat production can be obtained,” he added.