HOW would you feel if you had a little piece of pig beating inside your chest?
That is the remarkable prospect raised by a novel technique to refurbish pig organs with human tissue that could offer a new way to tackle the worldwide shortage of organs for transplant.
We certainly need to do something. This week there were 101,969 Americans . Many tens of thousands will die before they reach the top of the list.
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With the help of stem cell technology, we are learning to make tissues from scratch. Fashioning entire organs is another matter. To date, the major triumph has been the construction of a bladder, but building a much more complex organ this way looks almost unattainable.
Growing organs in pigs genetically engineered so that their tissues are compatible with those of human recipients has proved equally difficult. Now, as we report in this issue (鈥淗ybrid hearts for transplant鈥�), there is a halfway house, one which combines the skills of stem cell scientists with nature鈥檚 handiwork.
The idea is simple. Take an animal organ, say a pig heart. Chemically strip off all the flesh, leaving behind a collagen 鈥渃hassis鈥�. Then, recoat the naked pig heart with human cells, preferably the patient鈥檚 own so that the rebuilt organ is immunologically compatible. A first demonstrated the possibilities last year by creating a beating rat heart.
It might also be possible to customise compatible human organs this way, providing much wider opportunities for doctors to use organs from cadavers. Grief-stricken families would also have more time to make hard decisions about organ donation.
Some stem cell researchers doubt that the refurbished organs will have enough cellular diversity 鈥� blood supply and muscle cells may not be adequate, for example. But they will have to overcome similar challenges themselves.
And, a year after their pioneering work on rats, the Minnesota team has continued to make huge progress, even managing to plumb hearts with the blood vessels that they need to thrive. More groups are now attempting to create livers, muscles and hearts, with kidneys, pancreas and lungs further down the line.
鈥淭he Minnesota team has made huge progress, even plumbing hearts with blood vessels they need to thrive鈥�
Those who feel uneasy about hybrid pig-human organs should realise that millions of people are already walking around with much simpler implants made of pig tissue, such as heart valves. The potential of the new method is breathtaking. More than enough to make any hybrid heart skip a beat or two.