Lawrence Faucette, the second living person to receive a genetically modified pig heart in a transplant, has died six weeks after the experimental procedure. The University of Maryland Medical Center, where the experimental procedure had been performed, said the heart began to show signs of rejection in recent days.

“Mr. Faucette’s last wish was for us to make the most of what we have learned from our experience, so others may be guaranteed a chance for a new heart when a human organ is unavailable. He then told the team of doctors and nurses who gathered around him that he loved us. We will miss him tremendously,” Dr. Bartley Griffith, clinical director of the Cardiac Xenotransplantation Program at the University of Maryland School of Medicine, said in a statement. Griffith had performed the experimental surgery.