Successful Animal Kidney Transplants in Humans


The ever-persistent organ shortage crisis has long been a challenge in the field of medicine. Millions of people worldwide are affected by end-stage kidney disease (ESKD), a debilitating condition that necessitates kidney transplants for a chance at a healthier life. However, the demand for donor kidneys far exceeds the available supply, resulting in prolonged wait times and, tragically, the loss of many lives. In response to this critical issue, scientists have embarked on a remarkable journey, exploring the transplantation of pig kidneys into humans as a potential solution. Recent breakthroughs in this field have brought renewed hope for patients needing life-saving kidney transplants.

Kidney Disease and the Ongoing Organ Shortage

Kidney disease is a widespread health concern, affecting approximately 37 million American adults. Among these individuals, some progress to end-stage kidney disease (ESKD), a condition in which the kidneys lose their ability to function effectively. While kidney transplants remain the most effective treatment for ESKD, only a fraction of those in need receive this life-saving intervention. In the United States, where approximately 25,000 kidney transplants occur annually, the scarcity of donor organs poses a significant challenge. Tragically, nearly 40% of those on transplant waiting lists do not survive the five-year wait.

Xenotransplantation: Using Pig Organs for Humans

To address the critical organ shortage crisis, scientists have been exploring alternative sources of organs, and one promising avenue is xenotransplantation. This groundbreaking approach involves using organs from animals, specifically pigs, for human transplantation. Recent developments in xenotransplantation are now offering hope for patients waiting for life-saving kidney transplants.

  • Pig Kidneys Function Like Human Kidneys

In a groundbreaking study conducted by researchers from the University of Alabama at Birmingham’s Heersink School of Medicine, genetically modified pig kidneys were transplanted into deceased human recipients who had been declared brain dead. These pig kidneys had undergone genetic modifications to enhance their compatibility with human physiology. The recipients were administered immunosuppressive drugs to prevent rejection of the pig organs. Astonishingly, the pig kidneys started functioning within the human recipients’ bodies, producing urine and effectively filtering waste from the blood. Creatinine levels, a waste product that accumulates when the kidneys are impaired, decreased in the recipients after the transplant. Tissue samples from the pig kidneys displayed normal structures, indicating their proper function.

  • Genetic Modifications for Compatibility

These successful pig kidney transplants represent a significant milestone in the field of xenotransplantation. The genetic modifications performed on the pig kidneys enhance their compatibility with the human body. These modifications are carefully designed to minimize the risk of rejection and maximize the functionality of the transplanted organs.

  • Immunosuppression to Prevent Rejection

In addition to genetic modifications, the recipients of pig kidneys are given immunosuppressive drugs to prevent their immune systems from rejecting the transplanted organs. This critical step ensures that the pig kidneys can seamlessly integrate into the recipient’s body and perform essential kidney functions.

Ethical Considerations in Xenotransplantation

  • Balancing Animal Welfare and Medical Progress

Using genetically modified animals for organ transplantation raises ethical questions about the boundaries of genetic engineering. Dr. Kong notes that while the pigs used in these studies are genetically modified to be compatible with human physiology, their welfare remains a paramount concern. Pigs are intelligent, social animals, and their ethical treatment throughout their lives is of utmost importance.

  • The Role of Genetic Engineering

The genetic modifications performed on the pigs in this research, while ethically considered, serve a noble purpose: to address the severe shortage of human organs available for transplantation. Dr. Kong highlights that if ongoing research continues to show promise and successfully addresses ethical concerns, xenotransplantation could usher in a new era in the field of transplantation, offering hope and lifesaving solutions to countless patients awaiting organ transplants.

Surgical Procedures for Successful Transplant

To ensure that the pig kidney could function as the sole organ responsible for filtration, the recipient’s original kidneys were surgically removed before the pig kidney was transplanted. This surgical precision was instrumental in allowing the pig kidney to function effectively immediately after the procedure.

Overcoming Historical Challenges

In a parallel study, researchers at New York University Langone Health achieved a remarkable milestone by successfully implanting a genetically modified pig kidney into another brain-dead recipient. This engineered pig kidney continued to function effectively for a record-setting 32 days inside the recipient’s body, marking the longest duration of a genetically modified pig kidney working in a human. This achievement addresses previous challenges associated with xenotransplantation, such as immediate rejection due to mismatched biomolecules.

Ongoing Monitoring and Research

The researchers continue to monitor the results of this groundbreaking study, with observations and tests set to continue until mid-September 2023. This ongoing research will provide valuable insights into xenotransplantation’s long-term viability and effectiveness as a solution to the organ shortage crisis.

The Urgent Need for Solutions

These successful pig kidney transplants are significant in addressing the organ shortage crisis. Dr. Sabrina Kong, a veterinarian in San Mateo, CA, emphasizes the importance of these findings in bridging the supply-demand gap for kidney transplants, offering hope to countless patients who often endure lengthy wait times and, in some cases, unfortunate outcomes.


In the quest to alleviate the organ shortage crisis and provide hope to patients suffering from end-stage kidney disease, researchers have achieved remarkable milestones by transplanting pig kidneys into humans. These groundbreaking achievements signal a promising future for xenotransplantation and offer renewed hope to individuals eagerly awaiting life-saving organ transplants. As the journey continues, the ethical considerations surrounding this remarkable medical advancement will remain a focal point, ensuring that medical progress aligns with all beings’ welfare.


Reardon S. First pig kidneys transplanted into people: what scientists think. Nature. 2022 May 19.

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