A man in the United States has set a record by living for 271 days with a genetically modified pig kidney, before successfully receiving a human transplant. Tim Andrews, who faced a projected seven-year wait for a donor kidney and was told patients survive an average of only five years on dialysis, received the animal organ at Mass General Brigham hospital in Boston as a temporary measure. Doctors say the case advances the field of xenotransplantation (the use of animal organs in humans) and demonstrates that pig kidneys can serve as a "bridge" to keep patients alive while a human organ becomes available — a potentially vital development given that around 100,000 Americans are currently waiting for a kidney while only 25,000 transplants take place each year.