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University of Alabama at Birmingham News

Surgeons at the University of Alabama at Birmingham’s Comprehensive Transplant Institute transplant a genetically modified pig kidney into a human recipient. This photo was taken after reperfusion.

Xenotransplantation research marked a singular milestone last year with the first human transplants of kidneys and a heart from genetically engineered pigs. The genetic modifications were designed to improve transplantation outcomes by lessening immune rejection, controlling organ size and regulating complement, coagulation and inflammation. These pioneering surgeries were motivated by deficiencies of the current donor organ system, which have led to long waiting lists for organs (Fig. 1) and the deaths of thousands of patients in need of organs each year. Pig kidneys were transplanted into three brain-dead recipients — one at Legacy of Hope, University of Alabama at Birmingham1 and two at New York University Langone Hospital2. A pig heart was transplanted into a living recipient at University of Maryland School of Medicine3. The donor pigs, supplied by Revivicor, had either one gene knockout or a set of ten gene knockouts and transgenes (Table 1). What have we learned from these experiences, and how will they guide future research and surgical practice in the field? Are phase 1 clinical trials on the horizon? Experts in transplantation medicine, immunology and virology discuss the present state and future prospects of xenotransplantation.

Fig. 1: Transplantation figures in the United States.
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Number of people on waiting lists for four organs as of 27 February 2023. Also shown are the numbers of transplants performed in 2022. Source: Organ Procurement & Transplantation Network.

Table 1 Genetic modifications of donor pigs used for xenotransplantation

Joachim Denner is at the Free University Berlin in Germany; Jayme Locke is at the University of Alabama at Birmingham, AL; Chung-Gyu Park is at Seoul National University College of Medicine in South Korea; Richard Pierson is at Massachusetts General Hospital in Boston, MA; Jeffrey Platt is at the University of Michigan in Ann Arbor, MI; Angelika Schnieke is at the Technical University of Munich in Germany; and Linda Scobie is at Glasgow Caledonian University in the UK.

This roundtable was conducted by Laura DeFrancesco and Kathryn Aschheim.