A genetically modified pig kidney has been successfully transplanted into a human.

Organ transplantation is one of the most critical medical interventions for patients with end-stage organ failure. However, the global shortage of donor organs has prompted the search for alternatives, such as xenotransplantation—the transplantation of organs across species.

A Historic Milestone in Transplant Medicine

In a groundbreaking achievement, doctors have successfully transplanted a genetically modified pig kidney into a human patient. This breakthrough could revolutionize the treatment of end-stage kidney disease and bring new hope to thousands of people on transplant waiting lists.

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What Is Xenotransplantation?

Xenotransplantation involves transplanting organs, tissues, or cells from one species to another to compensate for the lack of human donors. Although this approach has been studied for decades, challenges like immune rejection, risk of cross-species infections, and hyperacute rejection have historically limited its clinical application.

Thanks to advances in gene editing technologies—particularly CRISPR-Cas9—scientists have now overcome several of these barriers by removing key pig antigens that cause strong immune responses in humans.

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The Case: A Genetically Modified Pig Kidney Transplant

A 62-year-old man suffering from kidney failure and on dialysis—who also had Type 2 diabetes, vascular disease, heart failure, and a history of a failed kidney transplant—was chosen for the procedure.

The transplanted kidney was sourced from a genetically engineered Yucatan miniature pig, with 69 gene edits, including:

• Removal of 3 glycosylation antigens responsible for hyperacute rejection.
• Inactivation of porcine endogenous retroviruses.
• Addition of 7 human genes to regulate immune response, blood coagulation, and inflammation.

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The Transplant Procedure

The surgery was performed at Massachusetts General Hospital under an expanded access protocol approved by the FDA and independent ethics committees.

According to a report published in the New England Journal of Medicine, the surgical procedure was successful:

• The cold ischemia time was 4 hours and 38 minutes.
• Within five minutes of revascularization, the kidney began producing urine—an immediate sign of function.

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Postoperative Results and Challenges

• Creatinine levels dropped rapidly from 11.8 to 2.2 mg/dl within six days, eliminating the need for dialysis.
• A rigorous immunosuppressive regimen was used, including thymoglobulin, rituximab, anti-CD154 and anti-C5 monoclonal antibodies, tacrolimus, mycophenolate mofetil, and prednisone.

However, on day 8, the patient experienced a T-cell-mediated rejection (Banff grade 2A), which was successfully reversed using high-dose methylprednisolone, additional thymoglobulin, and complement inhibitors.

The kidney functioned stably, maintaining an estimated glomerular filtration rate (eGFR) of 40–50 ml/min/1.73 m². Unfortunately, the patient died suddenly on day 52 from cardiac causes. Autopsy revealed advanced ischemic heart disease and ventricular fibrosis, but no signs of xenograft rejection or zoonotic infection were found.

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What This Means for the Future

This case represents a major leap forward in transplant medicine. The successful function of a genetically modified pig kidney in a human opens the door to addressing the global organ shortage crisis. It also paves the way for future xenotransplantation trials involving other organs, such as the heart and liver.

More clinical studies will be necessary to assess long-term safety, manage immune suppression, and monitor cross-species infection risks. Further understanding of how pig organs behave in the human body is also essential.

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Conclusion

The successful transplant of a genetically modified pig kidney into a human marks a historic achievement in medicine. While challenges remain, this breakthrough offers real hope for thousands of patients on transplant waiting lists. Ongoing clinical research and international collaboration will be crucial to turning this innovation into a safe, scalable, and global solution.