Successful xenotransplantation - 28th January 2022

The world's first successful animal to human heart transplantation, from a genetically modified pig to a 57 year old man, was carried out in Maryland, USA.

The extraordinary operation, undertaken by a team of surgeons at the University of Maryland Medical School, marks a major medical breakthrough in xenotransplantation and promises to remedy the lingering dearth of organ donations. 

Surgeon Bartley Griffith carried out the operation. 

Bartley Griffith: "The driver for all this was to provide an opportunity for patients with end-stage heart disease, who could not either qualify or just didn't get a heart in time, to treat their pretty poor heart function with a transplant."

Given his pre-existing health conditions, a human heart transplant was ruled out by surgeons for patient David Bennett. Nevertheless, his post surgical healing is going well but final results are anxiously awaited. 

The University of Maryland Medical School's director of the cardiac xenotransplant program, Muhammad Mohiuddin weighs in. 

Muhammad Mohiuddin: "We are all very excited to see this pig heart beating in this human. That pig heart has performed so far very well even beyond our expectations. We have not seen any signs of rejection."

Sourced from a herd which had undergone genetic editing, the pig had three genes which have resulted in porcine organ rejection in previous transplantation attempts, and a fourth which leads to excess pig heart tissue growth removed. The genome had an additional 6 genes from humans edited in, so as to ensure acceptance into the human body.  

With their size, large litters and fast growth, pigs are an optimal source for organ donation. 

Muhammad Mohiuddin is convinced that the fate of thousands of patients who die annually from the lack of available organs for transplant, will change with the advancement in xenotransplantation from genetically modified organs. 

Muhammad Mohiuddin: "We'll have these organs available, we can, you know, we have the technique of genetically modifying. So, if there's more tweaking required for modifying the genes, we will be able to do that, and you know, can customise, basically, the heart for all the organs for the patient."