Hope in Pig Liver
Organ donation is a high-risk, time-consuming, and costly endeavor. Countless people spend years on wait-lists, some never receiving an organ in time. There is a significant donor organ shortage, which might get even worse. And, even when an organ transplant can be accomplished, there is still the risk of rejection. One new method to counter these problems pushes forward the concept of "growing" organs; growing human organs from pig organs, by using pig organs as scaffolding for building new parts for humans.
Previously, efforts have been made to both grow organs from stem cells and genetically alter pig organs to be more human-like. And, while these efforts definitely pushed the potential of "grown" organs forward, a new study combining the concept from these two bodies of research is perhaps even more exciting.
Researchers at the US biotech firm Miromatrix are, in a new technique called “decel/recel,” dissolving the cells of ordinary pig organs to reveal their protein scaffolds. This allows for the original shape and structure of the organ to be maintained. Once the scaffold is all that remains, three types of human cells are introduced: liver cells, blood vessel wall, and bile duct cells. The cells naturally find their way to the correct place within this structure.
Jeff Ross, of Miromatrix, told New Scientist that the method “takes tissue engineering from a single layer to whole organs.”
So far, the team has reportedly successfully created livers using pig cells instead of human cells. These early test organs, when put back into living pigs, can be tested for rejection. It is highly unlikely that they will be rejected, because the animal's immune system wouldn't register a foreign object.
The team has now begun to experiment with introducing human cells, using cells from human umbilical cords to re-make blood vessels within the liver scaffold. When these reconstructed livers were implanted into pigs, the vessels survived and allowed blood to flow through the scaffold, before they were rejected for being made from human cells.
These results were presented at a meeting of the American Association for the Study of Liver Diseases in Washington DC this month.
This technique still has a long way to go, but the results it has so far ascertained give real hope in the field of organ creation. Laura Niklason of Yale University, who is using the decel/recel method to build blood vessels and lungs, told New Scientist: “The decellularisation and repopulation is not the tricky part–the tricky part is getting all the cells you put back in to behave properly.”
It is likely that this method will progress, and there is hope for a future where we can build organs. If this is true, then organ transplant wait lists might truly become a thing of the past.