Charlebois: Pig heart transplanted into human raises new ethical challenges

Breeding animals specifically to produce organs for people could level the field for those on waiting lists for life-saving treatment. But we need to ask some hard questions about xenotransplantation.

Sylvain Charlebois 4 minute read January 18, 2022

A team conducts a successful transplant of a genetically modified pig heart into David Bennett, a 57-year-old patient with terminal heart disease, at University of Maryland Medical Center in Baltimore on Jan. 7. UMSOM / via REUTERS

In an unprecedented surgery on Jan. 7, a 57-year-old American with serious heart disease had a heart transplant with a genetically modified pig’s heart. A few weeks later, the patient is still doing well, reports suggest. This surgical first, performed by a team from the University of Maryland School of Medicine, illustrates the feasibility of a pig-to-human heart transplant, a procedure made possible by new gene-editing tools. Science has given us xenotransplantation through gene editing.

Agricultural production has been helping feed humans since the beginning of time. It has also developed new vocations over the years, as with the energy industry, for example. Now, some researchers are contemplating animal production to help our health-care sector, in dire need of organs. At any given time, there are between 4,000 and 5,000 people waiting for an organ in Canada. And every year, between 200 and 250 people in Canada die waiting for an organ transplant. For the patient from Maryland, xenotransplantation was the only option as death awaited him. Xenotransplantation can save lives, as we now know, but some will surely ask questions about the ethical and moral aspect of breeding animals to produce organs to save human lives.

In Maryland, the university obtained emergency clearance from the U.S. Food and Drug Administration a week before the operation, under its compassionate use program. A few days later, the donor pig, raised in a hyper-sanitized environment, was slaughtered to extract its heart. Science can be amazing. It is likely, though, that the concept of a gene-edited pig, designed to produce a compatible organ for a human patient, will make some feel uneasy. The science is real, and a debate is warranted.

Discussions about xenotransplantation have been ongoing for years, but this is really the first time that we have had a successful operation by modifying a pig’s genetics to increase the chances of compatibility. For years, chimpanzee kidneys have been transplanted into some human patients, even a baboon heart into a baby, but the survival period has never exceeded a few months.

This is really the first time that we have had a successful operation by modifying a pig’s genetics to increase the chances of compatibility.

After a series of failures, the scientific community temporarily abandoned xenotransplantation until pigs were considered. Pork production lends itself better to xenotransplantation since it is possible to obtain an organ of adequate size within six months. In addition, several patients have already received valves and other parts from pigs in the past, with positive results. It’s not new, but to transplant an entire pig’s organ is unprecedented.

But before judging and condemning the practice as such, we must consider the egalitarian issue of transplants.

A hidden aspect of transplants is related to racialized groups. A Black, Asian or Indigenous person is less likely to get an organ donation than is a white person. Chronic diseases, genetics and blood history make it more difficult for them to find a donor. With animal gene editing to support xenotransplantation, it is scientifically more probable to produce a compatible organ for everyone, regardless of the genetic makeup of the person in need. In other words, xenotransplantation has the potential to further democratize organ donation.

In short, xenotransplantation supported by gene editing offers humanity a tailor-made organ donation system. But this practice also brings its share of other questions, especially in relation to the ethical treatment of animals. There is also always the risk of transmitting certain porcine viruses to humans. In light of the pandemic that we’ve all been living through for nearly two years, that’s no small consideration. We don’t know much about the genetic editing practices applied to the pig that allow the heart to stop growing once inside the human body. The company behind the technology, Revivicor, remains discreet. We also don’t know too much about what happened to the carcass of the donor pig, either.

This is a collective discussion worth having. Revivicor could have at least given the pig a symbolic name, like British researchers did with Dolly, the famous cloned sheep. After all, the pig is the real hero here.

Prof. Sylvain Charlebois is Senior Director of the Agri-Food Analytics Lab at Dalhousie University.



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