Surgeons have implanted a lung from a genetically modified pig in a human in a vegetative state, where it worked properly for more than a week. A great first which pushes the limits of a very promising technique, likely to have a significant impact on public health in the medium and long term.
According to the World Health Organization, only 10 to 20 % of people awaiting transplants end up benefiting from it, while the rest is forced to stay on endless waiting lists. Researchers therefore explore alternative sources, such as 3D culture or bioimpression of tailor -made functional organs from the patient’s own cells. Unfortunately, these techniques are still far from mature sufficiently.
In the meantime, specialists have started to take an interest in xenotransplantation (or xenogreffe), which consists in grafting an organ from a relatively similar species at the physiological level.
So far, the vast majority of these experiences have focused on pigsfor several reasons. The first is that their organs are quite similar to ours, both in terms of size and function. In addition, their genome has already been relatively well mapped, which allows researchers to make genetic changes to reduce the risk of rejection and infection.
Mixed clinical results
This field of research has already produced some promising results in recent years. In 2022, American surgeons successfully carried out the very first transplant of a genetically modified pork heart to improve compatibility. Two years later, Chinese doctors did the same with a liver, while another American team repeated the operation with a kidney.
To date, at least eight transplants of this kind were made, with Mixed results. In most cases, patients died a few weeks or months after the operation.
Unfortunately, this is also what happened during this first porcine lung xenogreffe. Twenty-four hours after the operation, carried out on a patient in a vegetative state, the organ began to undergo severe damage, probably due to inflammation linked to the procedure. He finally has stopped working nine days later, Unable to withstand the assaults of the immune system.
The lung, a particularly delicate graft
This result was unfortunately quite predictable. Indeed, during a transplant, the main difficulty is to ensure that the body will be accepted by the recipient’s organization. This is anything but obvious because of the immune system, which rigorously eliminates all foreign bodies to avoid infections and diseases. The organs from another individual, and a fortiori from another species, are therefore targeted directly by the immune system, leading to a violent and potentially fatal reaction: Rejection.
To limit the impact of these discharges, doctors use drugs that reduce the activity of the immune system. This approach works remarkably well for most internal organs. But the lungs unfortunately appear exception.
Unlike the heart or kidneys, the lungs are Designed to exist in contact with the outdoor environment – Inspired air, in this case. To play this role of interface correctly while protecting the body from toxic substances and pathogens, they must have a very efficient defense system. Inevitably, this complicates the transplants, where we try to put the immune system to sleep to avoid a rejection.
The researchers at the origin of this unprecedented procedure have had bitter experience, since their graft did not last long compared to other pork organs grafted in recent years.
New proof of encouraging concept
It would nevertheless be unfair to consider this essay as a total failure. Like other xenogreffe, it must be interpreted as a Evidence of encouraging concept. Even if we are still far from being able to fully replace conventional transplants, these works show that xenotransplantation could one day become viable in the long term.
All the challenge will therefore be to continue to refine these techniques, by identifying perfectly calibrated immunosuppressive cocktails and optimizing anti -rejection genetic modifications so that these grafts can function properly in the long term.
Admittedly, the road remains long, not to mention the ethical and regulatory debates that surround this field of research – but the game is worth the candle. It will be interesting to follow the evolution of these techniques which, once mature, could make it possible to save countless lives in a relatively close future.
The study text is available here.
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