Nature News reports that some experts are questioning the value of two recent experiments in which genetically modified pig kidneys were transplanted into brain-dead individuals.
Last October, researchers at New York University announced that they successfully grafted a pig kidney to a brain-dead individual without triggering that person's immune system and that that kidney produced urine. A team at the University of Alabama-Birmingham similarly reported in January that they transplanted a modified pig kidney into a brain-dead individual.
But some experts tell Nature News that the value of these experiments is limited. One issue, it says, is that the NYU team used a kidney from a pig with one genetic modification — to lack a glycan that typically activates an immune response, Reuters noted at the time — when additional changes are likely needed. The UAB team did use a kidney from a pig that underwent additional changes, and while that kidney too produced urine, it did not break down creatine, possible because the brain-dead individual's body was shutting down, it adds.
Because of this, experts tell it that clinical trials in living people might be necessary to answer outstanding questions, such as how the transplants fare over time.
As Nature News notes, a University of Maryland team recently transplanted a genetically modified pig heart into a heart failure patient. He lived about two months following the transplant and a pig virus is suspected to have contributed to his death.