Breakthrough in Xenotransplantation: Genetically Modified Pigs as Potential Organ Donors
Scientists from the Inpa Animal Biotechnology Laboratory (UBA-Conicet) and the Garrahan Hospital have achieved a major breakthrough in the realm of xenotransplantation. They have successfully created a genetically modified pig designed to circumvent hyperacute rejection, the most significant immune barrier encountered in animal organ transplants. This achievement opens new avenues for organ transplantation, especially for pediatric patients, who are increasingly facing severe shortages in donor organs.
The development comes against a backdrop of an urgent global crisis in organ availability. Over 5 million individuals worldwide are currently on waiting lists for organ transplants, yet only 120,000 transplants occur annually. The situation in the United States is equally dire, with 13 individuals dying daily due to the lack of timely organ transplants. In Argentina alone, approximately 6,000 patients were waiting for a renal transplant in 2020, with waiting periods often stretching between 7 to 10 years.
Moreover, data shows that over 70% of transplant recipients require dialysis within the first week post-surgery, indicating complications and delayed organ function.
The project, developed in conjunction with Garrahan Hospital, the leading center for pediatric transplants in Argentina, focuses on genetically modifying pigs to make their organs compatible with human biology. The experimental protocol involved perfusing a modified swine kidney with whole, anticoagulated blood, revealing promising signs of operation such as urine production and structural maintenance.
According to Dr. Ignacio Berra, a cardiovascular surgeon at Garrahan Hospital, this innovative approach aims to provide a specific solution for pediatric patients in need of compatible organs. “Currently, 1.5 million people are on the waiting list for solid organs, and only 10% are successfully transplanted. Genetically modified pigs will enable patients to wait for their organs more safely,” explained Berra.
During experiments, researchers also monitored several parameters, including perfusion pressure, renal diuresis, and vascular resistance, focusing on signs of thrombosis. Histological evaluations showed a noticeably lower degree of rejection tissues compared to unmodified organs.
At the heart of this innovation lies the editing of the GGTA1 gene, a key factor in causing hyperacute rejection. This gene, responsible for a surface molecule in pigs, triggers a significant immune response from humans. Utilizing the CRISPR-Cas9 technique, scientists successfully inactivated this gene, making it possible to eliminate the immediate immune response.
In January 2023, the first genetically modified pigs for xenotransplantation were birthed at the INPA laboratory. Alongside the GGTA1 gene modification, others have been edited for growth hormone (GHR) to produce smaller animals—making transplantation more feasible—and potentially offering increased resistance to conditions like diabetes or certain cancers.
The research demonstrates potential for kidneys to be connected to an ex-vivo perfusion system with human blood under physiological conditions. The modified organ was capable of filtering blood, producing urine, and displayed less inflammation and rejection than unmodified organs.
With xenotransplantation positioned as a groundbreaking solution to the organ shortage crisis, renewed interest has sparked globally. In pediatric medicine, where donor availability is critically low, the capability to transplant organs from genetically modified animals could save countless lives.
In 2022, the first porcine organ was transplanted into a human, but the recipient ultimately succumbed to complications. This situation underscores the crucial need for stringent health protocols in xenotransplant practices.
Researchers envision these genetically modified pigs as biological factories that could produce organs compatible with human uses. If their viability and safety are established, clinical protocols may soon follow. The immediate goals include advancing genetic edits, improving organ function trials across various organs, and collaborating with leading international medical centers, notably the Massachusetts General Boston Hospital, where significant clinical trials are already underway.
This research holds special importance for the pediatric demographic; out of 166 children awaiting transplants in Argentina, 98 require kidneys. Although the Justina Law has made strides in organ access for adults, family consent remains necessary for pediatric organ donation, complicating efforts in this realm. The innovative work conducted by Argentinian scientists represents a beacon of hope for countless patients.