As happened recently with the patient who received a genetically modified pig heart, this week science surprises us with the transplant of two genetically modified pig kidneys to avoid rejection by the immune system to a 57-year-old man brain-dead in the US The kidneys were not rejected during the 77-hour experiment.
The kidneys came from precisely the same line of genetically modified pigs that allowed David Bennett to survive since January 7; that is, they had the same genetic modifications. Although Bennett received the pig heart because there were no other options open to him (a case of life and death), the kidney transplant was performed solely as an initial test.
Most of these genetic modifications in animal organs are intended to reduce the risk that the human body will reject a transplant. For example, they lack three genes that code for specific carbohydrates that in the human body can trigger an aggressive immune reaction.
Jim Parsons , the current subject of the experiment, had been on life support since doctors declared him brain dead after suffering a traumatic head injury. Once permission was received from his family, since the subject was a registered organ donor, the scientists evaluated the possibilities of transplanting both kidneys to the patient.
To everyone’s surprise, the transplanted pig kidneys leaked blood, produced urine and, most importantly, were not immediately rejected by the patient’s body. The organs remained viable until the end of the study, 77 hours, or more than three days, after transplantation at the University of Alabama at Birmingham.
“This approach is based on the premise that such questions must be answered before clinical efficacy trials can be conducted responsibly,” the authors wrote.
The team, publishing their medical milestone in the American Journal of Transplantation, intends to transplant pig kidneys into living patients in formal clinical trials in the future, but they wanted to make sure about some critical safety issues first. To do this, they carried out an exhaustive control of the patient, observing if signs of rejection, virus transmission from the pig donor or surgical complications that could be exclusive to the pig-to-human procedure were detected.
“This human preclinical model is a way to assess the safety and feasibility of the pig-to-non-human primate model, without risk to a living human. Our study demonstrates that major barriers to human xenotransplantation have been overcome, identifies where they are needed. new knowledge to optimize the results of xenotransplantation in humans and lays the foundation for the establishment of a new preclinical human model for further study”, explains Jayme Locke, director of the Comprehensive Transplant Institute and principal surgeon of the investigation.
Referencia: “First clinical-grade porcine kidney xenotransplant using a human decedent model” 20 January 2022, American Journal of Transplantation. DOI:
10.1111/ajt.16930
