Using brain-dead people for medical experiments: The new debate at the frontier of bioethics

Four prestigious U.S. scientists have put a thorny but urgent question on the table. Working out of the universities of California and New York, they propose using the bodies of brain-dead people in hospitals to carry out medical experiments to advance research into treatments for currently lethal diseases. They explained in the journal Science that this strategy is already being used in an exceptional way to test the first transplants of organs from genetically modified pigs to humans in the U.S. and China, but they propose using these bodies to also test drugs, experimental DNA editing treatments and other modern gene therapies.

The four scientists — bioethicist Brendan Parent and neurologists Neel Singhal, Claire Clelland and Douglas Pet — argue that “hundreds, if not thousands, of simultaneous comparative experiments on a single physiologically maintained deceased” could be conducted. Dubbing the physiologically maintained deceased, PMDs, they go on to argue that “PMD research models, to our knowledge, have not been explored for new drug discovery, despite their considerable potential.”

In 1988, a team at New York’s Stony Brook university used the body of a brain-dead person to test a new anticoagulant treatment. Back then, that experiment sparked a debate about its moral and religious implications. In 2002, a group at the University of Texas MD Anderson Cancer Center used another body to produce a detailed molecular map of human blood circulation. These are the only published studies found by the four scientists.

Brain death involves the total and absolutely irreversible loss of brain functions. It has nothing to do with being in a coma, when the brain is still active. Brain death means, for all clinical and legal purposes, death, according to the Spanish Society of Intensive and Critical Care Medicine and Coronary Units.

The jurist Federico de Montalvo Jääskeläinen, who chaired the Spanish Bioethics Committee, the country’s highest advisory body in the field of scientific ethics until 2022, believes that just as it is possible to donate a corpse to science, it is possible to hand over the body in a state of brain death.

“The subject is formally and legally dead,” he says. “The problem is what can be done when there is no prior declaration or manifestation that it should be donated. Can the body of the individual be used? Can it be used when authorized by a family member? In this case, the issue becomes more complicated. One could even consider, as in the case of organ donation, an opt-out model, i.e.: we are all universal donors, unless we express our wish not to be.”

The image of multiple human bodies hooked up to machines may bring to mind apocalyptic sci-fi scenes, as in the movie Matrix, but the reality would be quite different. Brain-dead people would only be used with their prior authorization or that of their family, in intensive care units of university hospitals

The four U.S. scientists point out that brain-dead bodies are ideal for analyzing the effects of an intervention over days, but “the PMD research model would not necessarily be useful in longer-term studies, over months or years.”

De Montalvo Jääskeläinen argues that in the case of organ donations, the deceased donor’s respiratory activity is already maintained. “If research [with the bodies of brain-dead people] is comparable in terms of time length to donation, I don’t see a problem,” he says. “In short, in Spain, given our legal regime regarding organ donation, it can be accepted as long as the subject has previously authorized it, and the research is in the public interest.”

A month ago, a team of surgeons at the Xijing Military Hospital in the Chinese city of Xian announced the “success” of the first transplant of a transgenic pig liver into a person. The recipient was a brain-dead 50-year-old man. Similar operations with porcine hearts and kidneys have been underway since 2021 at New York University Langone Medical Center in the US.

Surgeon Pablo Ramirez, from the Hospital Virgen de la Arrixaca in Murcia, has requested authorization to transplant genetically modified pig livers into three people with fulminant liver failure if no human liver is available. “The model of a brain-dead human being with a beating heart is undoubtedly suitable for proof-of-concept testing of transgenic porcine organs,” he says.

Ramirez points out “two limiting factors” regarding this strategy. In his opinion, which is shared by the four U.S. scientists, the body of a brain-dead person should be used as a priority for organ donation, rather than for scientific research.

“The second limiting factor is the length of time that a beating heart can be maintained in a brain-dead person, which is no more than days or a few weeks at best,” he explains. “It is a model that possibly will not serve to investigate the long-term physiological functioning of transplants of transgenic porcine organs to the human species.”

But, he adds, it will serve to demonstrate that an experiment such as the one in China works and to facilitate the authorization of more ambitious trials, such as his own in Murcia, in which three people will receive pig livers for a few days, until a human liver from a deceased donor becomes available. For the four U.S. scientists, “the potential to advance science is tremendous.”

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