In what has since been dubbed a ‘landmark’ in medicine, the I surgery team at the University Synthetic Biology of Maryland School of Medicine (UMSOM), led by Dr Bartley Griffith, performed the world’s first pig heart transplant on David Bennett Sr. in January 2022. The team was granted special permission by the US Food and Drug Administration to perform the procedure on Bennett, who had terminal heart disease and was deemed ineligible to be added onto the heart transplant waiting list. Bennett’s heart transplant marks the first time a human receiving a pig organ is given the chance to survive and recover.
Xenotransplantation – the process of moving tissues between species – is being researched as a potential avenue to relieve the current organ donor shortages experienced around the world. Last year it was recorded that 474 people died while waiting for an organ transplant in the UK, with over 6,000 people currently on the waiting list. Bennett’s operation follows two other human studies with pig organs conducted by the University of Alabama and New York University in late 2021, where pig kidneys were attached to clinically brain-dead patients.
The heart used in the surgery came from a genetically modified pig raised and engineered by Revivicor, a regenerative medicine company based in Virginia. The pig contained ten genetic modifications (Figure 1), where four pig genes were inactivated and six human genes were added. One of the pig genes was deleted to prevent the heart from growing once implanted, while the other nine modifications aimed to prevent immune rejection and facilitate organ acceptance. It is uncertain how many of these modifications were essential for transplantation.
A few days after the operation in January, Bennett was able to sit up and showed promising signs of recovery. The surgery team regularly performed a range of innovative tests to monitor Bennett and his new heart’s condition. One such test used a DNA sequencer to scan his blood for fragments of pig genes, where an increase would indicate that the heart cells were dying. Another novel test developed by Karius screened his blood for traces of over 1000 pathogens.
Transplant Patient Dies
For the first month, Bennett seemed to be doing well and was able to It is also unclear where the virus may have come from, as the pigs were supposedly raised in a ‘pathogen-free’ facility. Revivicor has yet to make a public statement about this finding.
References
