On January 7, a 57 year old man with terminal cardiac failure underwent a nine hour operation at the University of Maryland School of Medicine and received a cardiac transplant from a pig. Three innovations made this historic procedure possible:
1. Genetic modification. Ten genes were changed in the pig: three were removed that would have caused a rapid, antibody-mediated rejection of the foreign organ; one was removed that would have made the heart too big; and six human genes were added to reduce inflammation, rejection and blood coagulation.
2. A perfusion solution to keep the porcine heart in optimal condition between operations. Apparently, this product contains cocaine which caused a regulatory headache for the researchers.
3. A powerful drug, KPL-404, that suppresses the body’s immunological reaction (in particular, CD-40) to the foreign organ.
The potential significance is enormous - many thousands die every year awaiting organ transplantation form human donors and demand will only increase - but there’s an army of potential problems ahead. One expert called the patient ‘courageous’ which is not something you want to hear.
On the medical side, rejection and infection are the two big immediate dangers. Rejection comes in three basic types - hyperacute, acute and chronic. The hyperacute stage seems to have been successfully navigated but the body has a myriad of responses to foreign antigens that are not fully understood.
An infection is made more likely because of the immunosuppressive medication the patient is on. This could be any extrinsic infectious agent or might have travelled in the transplanted organ itself. Longer term, one has to wonder how a heart from a quadruped will perform pumping blood all the way up to the head in a biped. Not a major worry right now.
There are ethical issues. If the patient dies in the next few weeks the decision to go ahead will be questioned; this is an experimental treatment and I’d say the surgical team are not getting much sleep at the moment. Some people may have concerns about any animal transplants to humans although I think we’re less bothered by that than we were and don’t expect to start hunting for truffles all of a sudden. There are also those may be put off specifically by a pig donor for religious reasons.
The patient was denied a human transplant partly because of poor compliance with treatment recommendations in the past, including management of hypertension. One aspect of the story dominating coverage at the moment is that the patient did time for a serious assault and the family of the victim are asking why a person guilty of a serious felony deserves such expensive care. Doctors would say they treat anybody regardless of their past.
https://www.dicardiology.com/videos/vid ... gery-humanBTW this is not the first time a surgeon has attempted such an operation. In 1997 an Indian surgeon had a go without the gene modification and other mod cons. The patient died and he was jailed.
https://timesofindia.indiatimes.com/hom ... 111349.cms