Is Xenotransplantation the Ultimate Cure for Kidney Disease?

A revolution in renal care

In the United States, millions suffer from chronic kidney disease, and ten patients die each day while waiting to receive kidney transplants (1, 2). Affecting 15% of adults in America, kidney disease is common, yet cures are limited. On March 21, 2024, surgeons and nephrologists (doctors who specialize in kidney care) at Massachusetts General Hospital (MGH) changed history. They transplanted a genetically-engineered pig kidney into a living human for the first time. This emerging field of xenotransplantation is a promising revolution in renal care (1). 

A diagram of a kidney (3). 

Kidneys are two bean-shaped, fist-sized organs located below the rib cage on each side of the spine (3). Healthy kidneys filter 142 liters of blood each day, removing harmful toxins and reabsorbing water, glucose, and essential amino acids (3). Each kidney has one million filtering units, or nephrons, that connect to blood vessels. Nephrons have two filters called glomeruli and tubules. Together, the glomeruli and tubules create a two-step process to purify and transport blood: the glomerulus filters the blood, and the tubule returns the needed substances, such as nutrients, to the blood while removing waste (3). Tubes of muscle called uretures connect the kidneys to the bladder, transporting extraneous liquid in the form of urine (3). In addition, kidneys produce erythropoietin, a hormone that helps form red blood cells while regulating blood pressure (4). 

 Diabetes, high blood pressure, and immune system diseases can trigger kidney disease, disrupting normal kidney function. An extreme form of kidney disease, End Stage Renal Disease (ESRD), is when kidneys can only complete 15% of their needed function (4). On average, people with ESRD require four-hour sessions of dialysis two to three times a week at clinics, hospitals, or in their own homes (5). Dialysis is a procedure where blood is removed from the body through a needle and sent through a two-piece filter that extracts the waste from the blood, mimicking the function of the kidneys (6). Following filtration, clean blood is injected back into the body with a tube (6). Although dialysis is a life-saving resource for millions, each session only accomplishes 10% of what a healthy kidney can do since it cannot correct the compromised function of the kidneys and only filters blood (5). 

Human-to-human kidney transplants, or allotransplantations, are promising alternatives to dialysis, with the potential for renewed kidney function following the surgery; however, 100,000 Americans are on a waiting list to receive an allotransplantation (2). Xenotransplantation, the process of transplanting live cells or organs from a non-human animal source (oftentimes pigs) into a human recipient, could correct the shortcomings of allotransplantations and transform the process of organ transplants (1). In September 2021, the New York University Langone Health Center experimented with xenotransplantation. Surgeons transplanted a genetically modified pig kidney into a brain-dead man. Seconds after implantation, urine was produced, a telling sign of a successful kidney transplant. In March, a xenotransplantation procedure at MGH saved Richard Slayman’s life, a 62-year-old whose extreme kidney failure affected his blood vessels, even after an allotransplantation (2). Biotech company eGenesis provided the kidney used in Slayman’s transplant. Scientists engineered and edited a pig kidney, removing three genes that could be involved in a potential rejection of the organ and inserting seven human genes to enhance compatibility (2). In addition, pigs have retroviruses (viruses that alter the host cell’s DNA) that are harmful to humans, so scientists at eGenesis inactivated these pathogens through gene editing (2).

Xenotransplantation for organ transplantation is not mainstream or FDA-approved yet because of concerns surrounding ethics and potential cross-species infections with retroviruses. Nevertheless, genetically-modified pig organs could transform transplantations for millions around the world. 


  1. (2022). Xenotransplantation. U.S. Food and Drug Administration. Retrieved from 
  2. (2024, March 21). Surgeons Transplant Pig Kidney Into a Patient, a Medical Milestone.The New York Times. Retrieved from 
  3. (2024, April 7). Your Kidneys & How They Work. National Institute of Diabetes and Digestive and Kidney Diseases; NIDDK – National Institute of Diabetes and Digestive and Kidney Diseases. Retrieved from
  4.  (2024, February 16).  Kidney Transplant. Retrieved from 
  5. (2023, December 15). Dialysis.  American Kidney Fund. Retrieved from
  6. (2019) Dialysis – hemodialysis Information | Mount Sinai – New York. Mount Sinai Health System. Retrieved from,about%20three%20times%20a%20week