GROWING hearts, kidneys, livers and lungs in the lab is still a long way off, despite the ballyhoo that greeted last week鈥檚 news that a Colombian woman had been fitted with a segment of windpipe made partly from her own stem cells.
A more practical and achievable alternative is now emerging, based on refining the work of the ultimate tissue engineer, Mother Nature herself. Great leaps have been made in 鈥渉umanising鈥� pig organs for transplantation (see 鈥淪aved by a pig鈥檚 heart?鈥�).
Researchers are now much closer to disguising pig organs through genetic tinkering, to prevent them from being attacked as 鈥渇oreign鈥� by the immune systems of human recipients. Some teams are also inserting genes to stop clotting and to damp down the local immune response. Whole organs are not quite ready to try out in humans yet, but they鈥檙e not too far off.
Advertisement
Another boon for the field will come from trials of pig cells to treat diabetes, which is likely to be the first mainstream use of 鈥渪enografts鈥�.
Spurred on by these remarkable signs of progress, in China last week researchers and regulators took a big step towards establishing a global set of guidelines for regulating xenotransplant research. They could help to pave the way to pig organs being transplanted into patients for the first time.
All in all, the field is experiencing a remarkable revival following its nadir a decade ago, when it was almost killed by fears that dormant viruses in pig DNA would spread to humans in transplants. The concerns that xenografts could lead to new diseases have now been largely allayed.
The bottom line is that stem cell science has serious competition 鈥� a sure sign that there will be progress. That should bring hope to the thousands of patients around the world who are awaiting new organs.