Reacción a "First pig-to-human lung transplant performed"

What do you think of the article overall?

"This study marks a milestone in translational medicine: for the first time, a genetically modified pig lung has been implanted in a brain-dead human. The organ, which underwent six genetic modifications to make it more compatible with humans, remained viable and functioning for nine days. During this time, no signs of hyperacute rejection or infection were detected, although complications did arise, such as primary graft dysfunction attributed to ischaemia-reperfusion injury and episodes of antibody-mediated acute rejection.

The significance of this advance lies in the fact that, until now, xenotransplantation experiments in humans had been limited to kidneys, hearts and livers, but never to lungs. This organ poses an even greater challenge due to its delicate physiological balance: it receives a very high blood flow and is continuously exposed to the ambient air, making it particularly vulnerable.

The authors of the study emphasise that this first published case is a key step, but not a definitive one. To make lung xenotransplantation viable in a real clinical setting, it will be necessary to refine genetic modifications, organ preservation techniques and the immunosuppression protocols used in the recipient. The challenge is enormous, but the work, rigorous in its design and development, opens up an unprecedented avenue towards new alternatives to the critical shortage of lungs for transplantation.

How does this fit in with existing evidence and what new information does it provide? What implications could it have?

"This new study is part of growing evidence that xenotransplantation—the transplantation of animal organs into humans—is technically possible, although it still faces significant challenges. Advances in gene editing (CRISPR) have accelerated this field in recent years, bringing it closer and closer to becoming a real clinical option. Nevertheless, it should be emphasised that it remains an experimental technique: to assess its efficacy and safety, it is essential to carry out more procedures in the context of carefully designed clinical trials with short-, medium- and long-term follow-up.

In this case, as in previous studies in the United States, the researchers used a brain-dead person as an experimental model, which allows them to study the viability of the graft in human conditions without risk to living patients. This model, which is of great scientific interest, always requires strict ethical and legal regulation.

The lung represents a unique challenge in the field of xenotransplantation. Unlike other organs that have already been transplanted experimentally—kidneys, livers and hearts—its high exposure to air and enormous blood flow make it more vulnerable and difficult to preserve. This is precisely why this study is particularly significant: it provides proof of concept that, with further improvements, lung xenotransplantation could in the future become a real option for saving lives. The clinical need is enormous. According to the Global Observatory on Donation and Transplantation (GODT), coordinated by the National Transplant Organisation (ONT) as a collaborating centre of the World Health Organisation (WHO), 8,236 lung transplants were performed worldwide in 2024, an increase of 6% over the previous year. However, demand far exceeds the availability of organs. In the European Union alone, 2,221 patients received a lung transplant in 2024, compared to 3,926 who remained on the waiting list throughout that year; of the latter, 216 died before receiving a transplant. In Spain, a world leader in this practice, 623 transplants were performed in 2024, representing a rate of 13.1 per million population, the highest rate in the world.

These figures illustrate the magnitude of the problem: every year, thousands of people face the possibility of not receiving the organ that could prolong and improve their lives in time. If xenotransplantation becomes established as a safe clinical option, it could radically transform access to lung transplantation and decisively alleviate the current organ shortage.

Are there any important limitations to consider?

"Yes, there are limitations, several of which are recognised by the authors themselves. First, oedema was observed in the transplanted organ at 24 hours, along with signs of acute antibody-mediated rejection. This highlights the need for further research and optimisation of different aspects of the technique, such as genetic modifications of donor organs, immunosuppression protocols and graft preservation strategies, which I have already mentioned.

Furthermore, it should be noted that in this study, a single animal lung was transplanted, while the recipient retained their native contralateral lung. This detail is not insignificant: the presence of a native organ could influence both the functioning of the graft and the immune response, limiting the direct extrapolation of the results to situations where a native lung is not retained.