A team of US researchers successfully transplanted two genetically engineered pig hearts into recently deceased humans in June and July this year.
On June 16 and July 6, the surgeries, known as xenotransplants, were performed at NYU Langone's Tisch Hospital, news agency IANS reported. The surgeries marked the latest advances toward addressing the organ shortage. In the future, a clinical protocol that would provide an alternative supply of organs for people with life-threatening heart disease could be developed.
It took several hours to perform the transplant surgeries, the IANS report said. For three days, the heart function was monitored.
Signs of early rejection were not observed in any of the hearts. Also, the hearts functioned normally with standard post-transplant medications and without additional mechanical support.
According to the report, the team of researchers said that using a new infectious disease protocol, no presence of porcine cytomegalovirus (pCMV) was detected in either case. This is an enveloped DNA virus.
"Our goal is to integrate the practices used in a typical, everyday heart transplant, only with a non-human organ that will function normally without additional aid from untested devices or medicines," Nader Moazami, surgical director of heart transplantation at the NYU Langone, was quoted as saying in the report.
"We seek to confirm that clinical trials can move ahead using this new supply of organs with the tried-and-true transplant practices we have perfected at the NYU Langone Transplant Institute," Moazami further said.
The team also carried out strict protocols to prevent and monitor potential zoonotic transmission of porcine endogenous retrovirus (PERV). This is a DNA virus present in the genome of all pigs and can infect humans.
The researchers procured the hearts from pigs that had 10 genetic modifications. These included four porcine gene "knockouts'' to prevent rejection and abnormal organ growth as well as six human transgenes ("knock-ins") to promote expression of proteins that regulate important biologic pathways which can be disrupted by incompatibilities between pigs and humans. The team did not use any other investigational devices or medications.
These latest advances in xenotransplantation move the field closer to realising a new supply of organs for those facing life-threatening disease, according to Alex Reyentovich, medical director of heart transplantation at NYU Langone.
"These are the first steps in developing a deep understanding of the mechanical, molecular, and immunologic aspects of xenoheart transplantation and the feasibility of utilising standard clinical practice and tools to do so," Reyentovich was quoted as saying in the report.