In a groundbreaking medical achievement, US surgeons have created history by performing the world's first successful transplant of a gene-edited pig kidney into a living human. This significant breakthrough in xenotransplantation, the transplantation of organs, cells, or tissues from one species to another, holds the potential to alleviate the global organ shortage crisis.

The procedure, announced last week, has drawn attention from experts who believe that gene-edited pigs could offer an unlimited supply of transplantable organs. Advocates of xenotransplantation see it as a viable solution to the growing number of patients on organ waiting lists worldwide. In Australia alone, there were 1,445 individuals awaiting donor kidneys in December 2023, while the United States reported over 89,000 patients waiting for kidney transplants.

However, not everyone is convinced that transplanting animal organs into humans is the definitive solution, nor is using organs from animals ethically acceptable. Two critical barriers hinder the success of xenotransplantation: organ rejection and the transmission of animal viruses to human recipients. Nonetheless, recent advancements in CRISPR/Cas9 gene editing technology offer hope in mitigating these challenges.

CRISPR gene editing, which harnesses a system already found in bacteria, has shown great potential in addressing the obstacles faced in xenotransplantation. In 2012, scientists discovered how to utilize the bacterial immune system's genetic scissors, known as CRISPR/Cas9, to edit and repair DNA at precise locations. This system can even introduce new genes at the repair site, offering remarkable possibilities.

In the recent xenotransplantation case, CRISPR technology was used to edit 69 genes in the pig donor, inactivating viral genes and removing harmful pig genes while incorporating human genes to "humanize" the pig. This remarkable achievement presents a critical development in the journey toward successful xenotransplantation.

While CRISPR editing has brought new hope to xenotransplantation, caution remains essential. Recent trials, including the transplantation of gene-edited pig hearts into two patients with terminal heart diseases, ended tragically with both patients passing away within weeks of the procedures. Nonetheless, other developments, such as a gene-edited pig liver transplant into a legally consenting adult, have shown positive results within the trial period.

With the increasing focus on gene-editing, medicine and gene technology regulators have been presented with requests for approving experimental trials that employ CRISPR editing. It's crucial to note that neither xenotransplantation nor therapeutic gene editing leads to changes in the genome that can be inherited. The creation of inheritable gene alterations would necessitate editing early-stage embryonic cells, which is currently a criminal offense in Australia and prohibited globally.

Despite the immense potential, xenotransplantation using CRISPR technology is still in its early stages. While the recent US transplant was authorized under the "compassionate use" exemption, conventional clinical trials for pig-human xenotransplantation are yet to commence. Significant improvements in outcomes will be necessary to gain regulatory approval for official trials and the availability of off-the-shelf xenotransplantation organs, including gene-edited kidneys, is likely to take some time.

As the race to revolutionize transplantable organs intensifies, the medical community remains committed to further exploration and refinement of xenotransplantation techniques. While challenges and ethical concerns persist, this groundbreaking achievement signifies a crucial milestone in medical history, offering hope to patients in dire need of life-saving organ transplants.