What?
Organ transplantation saves millions of people a year, from young to old, transforming many lives and giving hope. Thanks to doctors and scientists, our NHS has pioneered great advances in transplantation surgery that make it very safe and allow some recipients to survive for 20 years or more.
Transplantation surgery often involves removing an organ from one human and placing the organ into another human (allogenic transplant). This type of surgery is the best treatment for many patients with end-stage kidney failure (ESRF), who need a kidney to improve their quality of life. And it can be life saving for patients with advanced heart failure. While this surgical method is very effective, there are multiple barriers to organ transplantation – one being a lack of available human organs.
Surgeons in the US announced this month that they had performed a successful transplant of a pig heart into a human (xenotransplantation). It is still unclear how well or how long the heart will function, but this technique may be the new lifeline for patients who cannot find organ donors.
This type of transplant is not new. In fact, some of the first transplants were from animals. In Lyon, in 1906, Mathieu Jaboulay carried out the first xenograft kidney transplants using pigs and goats as donors. The organs were transplanted into the arm or thigh of patient with ESRF. He used suturing techniques pioneered by his student Alexis Carrel who later won a Nobel Prize for this work.
Why?
The announcement of the first pig-to-human heart transplant is a big deal. Hundreds of people a year are on the organ donation list waiting for suitable organs, and sadly some pass away whilst waiting due to the progression of their disease. Some of the most common conditions requiring transplantation include advanced heart failure and end-stage renal failure.
The biggest barrier to organ transplantation is lack of organ donation. To improve transplant numbers, the UK government (in 2019) announced that all adults in England would be considered to have agreed to be an organ donor when they die unless they have recorded a decision not to donate or are in one of the excluded groups.
One of the reasons a human organ is usually used in transplantation is that the recipient’s body is less likely to reject it. Even with human organs, patients who are transplant recipients require very strong medication to suppress their immune system and prevent rejection. The pig heart in this case was genetically modified by adding human genes to reduce the risk of transplantation.
This may be a game changer. If this can be done for many people, it would mean less reliance on humans to donate and (possibly) less use of anti-rejection drugs. But this type of transplant is not without its issues: zoonotic viral infection from pig to human is possible, with a special concern regarding pig endogenous retrovirus (PERV). After COVID-19, do we really want to take that risk? There are also ethical concerns that merit wider public debate – is it right to breed pigs just to take their hearts for human use? One to ponder on…
How does it affect you?
Animal to human organ transplantation has been attempted on and off for decades, but never perfected. We still have a lot to learn. At this point, the patient who received the pig heart is still alive (two weeks post-operation at the time of writing). Further studies are required to assess how long these patients can survive, and how feasible this would be for the wider population. This fascinating new technique may help open doors to further bioengineering which could one day benefit a whole range of conditions.
If you’d like to read the paper, you can access it here: https://www.bbc.co.uk/news/world-us-canada-59944889
As always, best wishes from myHSN.
