Thomas Starzl, MD, PhD, the man who performed the world’s first liver transplant and was a leading researcher of antirejection drugs, has died. He was 90 years old, The Los Angeles Times reports. 

Starzl, a legendary surgeon, pioneered the liver transplant in 1963 and performed the world’s first successful liver transplant in 1967. Starzl also pioneered kidney transplantation from cadavers and later perfected the process of organ transplantation using identical twins and, eventually, other blood relatives as donors. Since then, thousands of lives have been saved from procedures based on the doctor’s research. 

Starzl’s lifelong career in liver surgery began while he was a resident at Johns Hopkins Hospital in Baltimore, where he assisted on an operation aiming to redirect blood flow around the liver for a surgery. After the procedure, Starzl began animal experiments in 1956, which laid the foundation for his first liver transplants at the University of Colorado in Denver seven years later.

In 1981, Starzl joined the University of Pittsburgh School of Medicine as a professor of surgery. While there, his studies on the antirejection drug cyclosporin in combination with steroids offered one of the first major solutions to the threat of organ rejection. Starzl’s other accomplishments in the liver research field include studies on animal-to-human transplants, the development of the use of the antirejection drug FK506 and integral research at the cellular level on how the body is able to accept a foreign organ.

In 1990, at age 65 and shortly after the death of a young heart-liver transplant patient, Starzl retired from surgery. Until 1991, Starzl served as chief of transplant services at the University of Pittsburgh Medical Center. He was then made director of the University of Pittsburgh Transplantation Institute, which was renamed the Thomas E. Starzl Transplantation Institute in 1996.

According to the University of Pittsburgh, which spoke on his family’s behalf, the renowned doctor died of natural causes at his home in Pittsburgh last week. Starzl is survived by his wife of 36 years, Joy Starzl; his son, Timothy; and a grandchild.