Doctors at NYU Langone Health in the US have discovered a way to reverse the rejection of organs transplanted from pigs to humans, so-called xenotransplants, they announced in an article in Nature on Thursday. Previously, it was thought that available treatments could not stop rejection once it started.
Experimentally, the researchers transplanted a modified pig kidney into a recipient who was already brain-dead. The recipient’s heart was beating and he was connected to a ventilator. These conditions allowed continuous monitoring of the immune response to the transplant, and the organ remained functional for 61 days.
Researchers monitored tissues, blood, and body fluids to understand how the body tries to fight foreign substances. The material revealed that the reaction occurs in a fluid manner, with moments of resistance and moments of attack on the pig’s organs, which could potentially stop rejection.
Clues about first refusal
The first study looked in detail at the interaction activity between human and pig tissues. Research shows that T cells monitor initially unknown tissues, marking them for destruction and attacking specific structures. This process caused a sudden decline in kidney function in the recipient.
The research team used immunosuppressants to reverse the immune attack. After treatment, the kidneys began to function again without showing signs of permanent damage, and thanks to a plan that intervened only in the course of the attack, it was possible to better preserve the defense system and the organ at the same time.
Surgeon Robert Montgomery, the study leader, told the hospital’s website that the discovery would accelerate the use of pig organs in medicine. “With these results, we are now better equipped to predict and address adverse immune responses when transplanting pig organs into living humans,” he says.
Detailed mapping of the body’s defenses
In a second article published on the same date in the same journal, the team described genetic analysis of transplanted kidneys. The research team measured about 5,100 genes in humans and pigs. Data integration has provided a complete picture of immunological responses and established associations and contradictions between them.
The transplant took place on July 14, 2023, and the researchers observed three different immune attacks. On the 21st day, an innate response was observed from the recipient. On day 33, macrophages, which are destroyed human cells, engulf the pig’s kidney cells and attempt to kill them. The team thwarted that performance. On day 45, T cells intervened again, leading another attack.
“The specific immune responses uncovered in our study provide pigs and humans with clear targets for treatments aimed at improving the success rate of xenotransplantation and addressing the severe shortage of available organs,” concluded study lead author Dr. Brendan Keating.
What is xenotransplantation?
This is the first clear evidence of reversal of organ rejection after using focal-only therapy. This protocol is important because the use of pig organs to treat diseases is considered a new frontier in medicine.
Recently, modified pig hearts, livers, kidneys, and thymus glands have been transplanted into living patients. Several organs lost function or were removed, and in many cases, recipients died soon after surgery. Despite this misfortune, this cannot be considered a procedural error, but rather a result of the volunteer’s already weakened health at the time the procedure was performed.
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