October 22nd 2021
Those of you who read the SR blog will be familiar with the #TimeScales that are often involved in bringing cures from bench to bedside and that often these cures were made possible by animal research #MPAR. A recent news story highlighting a successful pig kidney transplant in a human patient is no exception. We congratulate the Guardian for highlighting the vital role that animal research has played and will continue to play in bringing this breakthrough to fruition.
What did they do?
In a first ever, surgeons were able to attach a pig’s kidney to a deceased human (cadaver) and observe it functioning. A deceased human’s organs can continue to function through artificial life support, even though the patient has experienced brain death. With patient or surviving family consent, doctor’s may be given permission to perform an experiment such as this one. Here, they attached the pig’s kidney to the renal artery and renal vein and were able to observe the kidney filter waste and produce urine—but most importantly, no organ rejection was observed.
Why is this important?
First, this procedure is a proof of principle procedure. That is, it is the first in a long series of steps that must be undertaken before being trialled in a living human. One of those steps is actually observing whether we can observe long term kidney functioning without rejection. Second, the organ crisis globally is dire. It is estimated that 20 Americans die each day because of the unavailability of organs for transplant.
How did we get here?
Animal to human transplants (xenotransplantation) can be traced back to the 17th century in terms of blood transfusion (another shortage globally). We have written about the pioneering work of Thomas Starzl in the early 20th century—the father of organ transplants in humans—and how formative research in dogs and pigs made this possible. Since then, research in other animals—looking toward xenotransplantation without organ rejection—has been performed. For example, using lab grown bile ducts and fecal transplants from the organ donor are all procedures that build upon the formative basic research in animals on organ transplantation which is then further refined (to limit the chance of rejection), again using animals.
This study in particular was #MPAR because of a gene editing technique pioneered in animals. Here, this gene-edited pig had a sugar molecule in its cells removed because it is not found in humans. Removing that sugar molecule meant that the potential for organ rejection was minimized. In order to understand that pigs have this sugar in its cells and humans do not, however, meant that comparative research in both species needed to be performed. Another example of the #TimeScales involved in animal research.
What does the future hold?
According to the Guardian:
“Experts say tests on nonhuman primates and the experiment with a human body pave the way for the first experimental pig kidney or heart transplants in living people.
Raising pigs to be organ donors feels wrong to some people, but it may grow more acceptable if concerns about animal welfare can be addressed, said Karen Maschke, a research scholar at the Hastings Center, who will help develop ethics and policy recommendations for the first clinical trials under a grant from the National Institutes of Health.”
These are fundamental questions that we as a society must tackle together. Currently, however, the majority of the American public support the growing of organs/tissues in animals for humans needing a transplant.
~Speaking of Research