In the last few days many newspapers had in the headlines the (so far) successful transplant of a pig heart into a human. It is a first in xenotransplantation (transplant from a different species) and for sure it is worth making the headlines. There was a pig-heart human transplant in October 2021 in a brain dead patient (in New York) but that one had the goal of testing the surgery procedure, this one had the goal of saving a human life.
What impressed me, reading the articles and then digging the web to get more detail, is what the whole procedure involved.
The problem with transplant, that skyrocket in xenotransplant, is the rejection of the transplanted tissue/organ by the receiving body. This is a safe mechanism allowing our survival in the fight against viruses, bacteria and anything that manages to sneak into our body: recognising the intruder as such and mounting a defence with the goal of rejecting it.
In order to “fool” the immune system the approach since the beginning of transplant has been to depress the immune system of the receiver to avoid the rejection. This approach works, but it also has the unwanted side effect of lowering the body defences against any other intruder.
This time scientists have approached the problem in a complete new way: they have found what are the stimuli that prompt the immune system to recognise a foreign object and obliterate them. This approach, if successful, could in principle solve the rejection problem.
In this particular case they have used bio-engineering to “kill” the genes in the animal tissue (heart) that create the proteins recognised by the receiver immune system as an external body and those that are active in the donor tissue to recognise a foreign body (the heart surrounded by a foreign body).
It is this use of bio-genome-engineering that has impressed me most. After the mRNA vaccine we have now another concrete evidence that scientists have the technology to manipulate the code of life, turning it on and off and tuning it like a computer to perform specific tasks. We already have many examples of using CRISPR/Cas9 to direct bacteria developing specific proteins. Now we are using the understanding of genes roles to modify the “programs” of cells to fit our needs.
This opens up amazing opportunities for the future of healthcare.