The pigs had already been dead for an hour, and yet their heart, brain, and liver cells were still kicking.
Thanks to a new system called OrganEx, scientists can now preserve the dying organs of recently deceased people pigs alive by connecting the animals to a system of pumps, filters and circulating fluids. This procedure does not restore animals brain operate or remove the pigs from the great beyond; rather, it ensures the maintenance of certain cellular functions in the vital organs of animals.
In the future, the system could potentially be used to help preserve and restore donated human organs for use in transplant procedures, scientists have reported in a new study, published Wednesday (August 3) in the journal Nature (opens in a new tab). This process could increase the number of organs available for transplantation by reversing the effects of ischemia – in which an organ suffers damage due to some blood oxygen flow and supply – in donated organs.
And in theory, such a device could also be used in living humans to treat the ischemia that occurs during a stroke or heart attack, Dr. Robert Porte, a professor in the department of surgery at the University of Groningen in the Netherlands who was not involved in the study, wrote in an accompanying comment (opens in a new tab) work.
However, the technology won’t be applied to living humans or organ donations anytime soon.
“It’s a long way from being used in humans,” Stephen Latham, director of Yale’s Interdisciplinary Center for Bioethics and co-author of the study, told reporters at a press conference Tuesday, August 2. . The proof-of-concept experiment in pigs demonstrated that the OrganEx system can restore certain cellular functions in certain organs after blood has stopped flowing to those organs, but the degree of recovery differs from organ to organ. .
“We should study [in] much more detail about the degree to which ischemic damage is reversed in different types of organs before we’re even about to attempt an experiment like this on a human being who has suffered anoxic damage.” that is, organ damage due to a lack of oxygen, Latham says.
The team plans to study OrganEx in many more animal studies “before we even think about translating” the technology to humans, said Dr. David Andrijevic, a neuroscience associate researcher at Yale School of Medicine and co-first author of the study. at the briefing.
How OrganEx Works
The new research builds on a previous study, published in 2019 in the journal Nature (opens in a new tab)in which researchers used a smaller version of the same system to restore certain cellular elements and metabolic activity in the brain of a pig that had been decapitated during food production.
This smaller system, called BrainEx, pumped a liquid filled with Hemopure – a synthetic form of the protein hemoglobin, which carries oxygen in red blood cells – through blood vessels in the brain. The liquid also contained chemicals intended to prevent blood clots from forming and cells from self-destructing through a process called “apoptosis”. Pumping this fluid through the brain prevented the organ from swelling, as it usually would after death, and allowed some cellular functions to continue for up to four hours after decapitation. (Importantly, the treated brain produced no electrical signals associated with normal brain function or “residual consciousness,” the authors confirmed.)
“Cells don’t die as quickly as we assume, which essentially opens up the possibility of intervention,” said Dr. Zvonimir Vrselja, associate neuroscientist at Yale School of Medicine and co-first author of the study, said at Tuesday’s press conference. In other words, if scientists can intervene early enough, they can save certain cells from a certain fate.
In their latest work, the team essentially scaled up their BrainEx system to perfuse an entire pig body at once.
The scaled-up system uses a heart-lung machine-like device, which takes over the role of the heart and lungs during surgical procedures by pumping blood and oxygen through the body. The team used this device to pump both pig blood and a modified version of their cell-preserving synthetic fluid through the bodies of deceased pigs. Their synthetic solution contained 13 compounds intended to suppress inflammation, stop blood clots, prevent cell death and correct electrolyte imbalances that occur when ischemia sets in.
To test OrganEx, the team caused cardiac arrest in anesthetized pigs, then after an hour they connected the animals to the device. They compared pigs treated with OrganEx to pigs treated with an extracorporeal membrane oxygenation (ECMO) system, which pumped only oxygenated blood through the animals’ bodies.
After six hours, the team found that the ECMO had not sufficiently perfused all of the animals’ organs with blood and that many blood vessels had collapsed, as they typically would after death; ECMO-treated animals also showed extensive signs of hemorrhage and tissue swelling. In comparison, OrganEx reduced the degree of cell death and improved tissue preservation throughout the body.
Additionally, pigs treated with OrganEx showed signs of cellular repair taking place in the brain, heart, lungs, liver, kidney and the pancreas, and these vital organs retained some cellular and metabolic functions during the six-hour experience. The heart, in particular, showed signs of electrical activity and was able to contract. Closer examination of pig hearts, kidneys and livers also revealed that specific genes involved in cell repair were activated in the organs, whereas they were not in the pigs treated with ECMO.
“What this tells us is that cell demise can be halted and functionality restored in several vital organs, even an hour after death,” said Dr. Nenad Sestan, professor of neuroscience at the Yale School of Medicine and lead author of the study. , said during the briefing.
The results suggest that one day OrganEx or components of the system could be applied in the treatment of ischemia and in the preservation of transplanted organs, particularly in the case of “donation after circulatory death”, in which the donated organs were deprived of blood. circulation for some time before the transplant, writes Porte in his commentary. But again, much more research is needed before the system can be applied in either setting.
In follow-up work, the research team wants to better understand how, where, and to what extent OrganEx restores cellular function in different animal organs. Additionally, they will need to assess if and how their synthetic solution should be suitable for use in human tissue. And ethical and practical concerns must be addressed before even considering using the system in living humans, Latham said during the briefing.
“You have to think, ‘What state would a human being be restored to if they had been badly damaged by ischemia and you gave them a perfusate that reversed some, but not all, of that damage?’ “, did he declare. . “Organ salvage and the maintenance of organs for transplantation is, I think, a much closer and much more realistic clinical goal that could be based on this study.”
Originally posted on Live Science.