A Chinese patient is the third person in world known to be living with a gene-edited pig kidney, with the research team also reporting an experiment implanting a pig's liver into a brain-dead person.
Two initial xenotransplants in the US – two pig hearts and two pig kidneys were short-lived, reports AP. But two additional pig kidney recipients so far are thriving: an Alabama woman transplanted in November and a New Hampshire man transplanted in January.
Nearly three weeks after the kidney surgery the Chinese patient “is very well” and the pig kidney likewise is functioning very well, said Dr Lin Wang of Xijing Hospital of the Fourth Military Medical University in Xi’an last week.
Wang, part of the hospital’s xenotransplant team, said the kidney recipient remains in the hospital for testing. Chinese media have reported she is a 69-year-old woman diagnosed with kidney failure eight years ago.
But Wang pointed to a potential next step in xenotransplantation – learning to transplant pig livers. His team reported recently in the journal Nature that a pig liver transplanted into a brain-dead person survived for 10 days, with no early signs of rejection. He said the pig liver produced bile and albumin, which are important for basic organ function, although not as much as human livers do.
The liver is a complex challenge because of its varied jobs, including removing waste, breaking down nutrients and medicines, fighting infection, storing iron and regulating blood clotting.
“We find that it could function a little bit in a human being,” Wang said, saying they had speculated that it would be enough to help support a failing human liver.
In the United States last year, surgeons at the University of Pennsylvania attempted that sort of “bridge” support by externally attaching a pig liver to a brain-dead human body to filter blood, much like dialysis for failing kidneys. American pig developer eGenesis is studying that approach.
In China, Wang’s team didn’t remove the deceased person’s own liver, instead implanting the pig liver near it.
“That clouds the picture,” said Dr Parsia Vagefi, a liver transplant surgeon at UT Southwestern Medical Centre who wasn’t involved with the work. “It’s hopefully a first step but it’s still, a lot like any good research, more questions than answers.”
Wang said his team later replaced the human liver of another brain-dead person with a pig liver and is analysing the outcome.
According to media reports, another Chinese hospital last year transplanted a pig liver into a living patient after a piece of his own cancerous liver was removed, but it’s unclear how that experiment turned out.
See more from MedicalBrief archives:
Genetically engineered pigs put xenotransplantation back in the spotlight
Second person to receive transplanted pig kidney dies
First combined heart pump and pig kidney transplant