Surgeons at the University of Alabama at Birmingham have successfully transplanted kidneys from a genetically modified pig into the abdomen of a 57-year-old man, who was clinically brain dead.

According to the New York Times, the kidneys functioned well without signs of rejection. The landmark procedure occurred just weeks after University of Maryland surgeons completed a successful pig-to-human heart transplant.

Researchers believe that organs grown in genetically modified animals could potentially save countless lives. In the United States alone, more than a dozen people die every day while waiting for a kidney transplant.