http://www.newscientist.com/article/mg21829132.800-what-happens-when-hearts-become-spare-parts.html

• 18 April 2013
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Lab-grown organs could be a boon for those on transplant waiting lists – but they also raise ethical questions

THE first heart transplant, back in 1967, was as shocking to some people as it was wondrous to others. The use of parts from one person to heal another – especially culturally resonant parts from dead donors – was a viscerally unsettling prospect.

Today, most of us consider a transplant to be a boon, albeit one that can only be granted to a limited number of people. Despite concerted efforts to increase the supply of donor organs, waiting lists are still lengthy in many places. What a further boon it would be, then, if we could make as many organs as we needed.

In this respect, the successful implantation of a lab-grown kidney in a rat this week is good news. Researchers are working hard to make the same techniques work with other organs – and in humans (see "Lab-grown kidney blazes trail for bespoke donor organs").

Even if all goes smoothly, it will be a long time before we take the first step: renewing donated organs that would otherwise go to waste because they are unsuitable for would-be recipients or in poor condition. These organs could be made viable by stripping them of donor cells, then recoating them with a patient's own.

This will not in itself solve the organ shortage. In the US, for example, around 18 per cent of donated kidneys go unused. Adding these to the 18,000 transplants conducted each year won't eliminate the 100,000-strong waiting list, although it will save many lives.

There is an alternative, albeit more distant. We could harvest organs from animals (most likely pigs) which can be stripped and then "humanised". If it works, this could let us meet the demand for organs in its entirety.

Would patients, and society, accept this? Almost 20 years ago, a front cover of asked: "Will a pig's heart end up in you?" That question remains open, as direct transplantation of major organs across species boundaries still hasn't been made to work.

But millions of people today do have body parts derived from pigs, such as heart valves and hernia patches. Pragmatism has won out over squeamishness, and acceptance will probably keep growing. The time may well come when the transplant of an animal's heart, too, seems more wondrous than shocking.