Breakthrough in Genetically Modified Pig Lungs for Human Transplant

Scientists have recently announced their success in keeping a genetically modified pig lung alive inside a human body, albeit for a brief period. This achievement is seen by some as an early step towards a long-awaited medical breakthrough, although others caution that there is still a long way to go.

Challenges of Animal-to-Human Organ Transplants

With the increasing demand for human organs far exceeding supply, scientists have been attempting for decades to turn pigs into life-saving donors. Many pig organs are similar in size and structure to human organs, and pigs reproduce quickly and can be raised in disease-free environments. Researchers have successfully transplanted pig kidneys, livers, and hearts into humans, but lungs have posed a significant challenge due to their physiological complexity.

Lungs contain numerous blood vessels and white blood cells known as macrophages that engulf and destroy bacteria and viruses. These cells produce immune responses rapidly, but they also tend to trigger fast and potentially lethal inflammation when blood flow is restored after being reduced during transplant surgery.

Experimental Steps for Genetically Modified Lungs

A team of scientists at Guangzhou Medical University in China transplanted a pig lung into a 39-year-old recipient who had been declared brain-dead. The researchers used CRISPR gene-editing technology to modify three pig genes targeted by human antibodies and added three human genes to help prevent rejection.

The transplanted lung functioned for nine days and was not immediately rejected by the human body. However, scientists reported signs of lung tissue damage one day post-surgery due to oxygen deprivation during the transplant, with initial signs of antibody-mediated rejection appearing on the third and sixth days.

Improvements Needed for the Future

The authors explained in a study published in Nature Medicine that significant improvements are needed, such as enhancing the genetic modifications in pigs and the immunosuppressive drugs used to avoid long-term organ rejection. None of the authors responded to interview requests from Scientific American.

Some experts believe that additional genetic modifications should not be made blindly. Instead, each modification should be tested separately by transplanting organs into baboons, a primate often used as a test step before human trials.

Future Advances in Animal-to-Human Organ Transplants

The recent easing of regulatory laws in some countries has expanded opportunities for surgeons to attempt pig-to-human transplants. More such procedures are likely to be attempted in the coming years.

Recent years have seen successful pig kidney transplants into humans, with these organs functioning relatively well. Currently, two people are living with pig kidneys, one in China since March and another in the United States since January.

Conclusion

This achievement is a challenging yet necessary first step in developing pig-to-human organ transplants that could one day save thousands of lives. Although progress will be slow, each step in this field is crucial.