Scientists from the University of Edinburgh in Scotland have claimed to have grown kidneys in a laboratory by manipulating stem cells, a major breakthrough which could help tackle the shortage of organs for transplant. The newly created organs measure half a centimetre in length – the same size as a kidney in a foetus; and, the team hopes the tiny kidneys will be able to grow to maturity after being transplanted into human bodies. The team of scientists has actually used stem cells, which are the building blocks of the body, to form the structure of kidneys. In fact, the kidneys were grown in the lab using a combination of cells from amniotic fluid – the fluid which surrounds all babies in the womb – and animal foetal cells. The technique holds out the prospect of doctors being able to collect amniotic fluid at birth to be stored until needed at a later date if a patient develops kidney disease, say the scientists. The patient's own amniotic fluid cells can then be used as the base for creating a new kidney. Using the patient's own cells will also end the problem of rejection that arises when an organ from a deceased donor is used. Team leader Prof Jamie Davies said: “The idea is to start with human stem cells and end up with a functioning organ. If you have got a bunch of stem cells sitting in a test tube, that's a long way from being a beautifully, anatomically organized organ like a kidney that is a complicated structure. “So we are working on how you turn cells floating about in liquid into something as precisely arranged as a kidney. We have made pretty good progress with that. We can make something that has the complexity of a normal, foetal kidney, but not an adult one yet.” To get to the stage where transplants into humans may be possible, research teams in Scotland and the US have been working on the different techniques required. A team in Michigan has taken embryonic stem cells and manipulated them, using chemicals, to become kidney stem cells. Using a related technique, the scientists in Edinburgh were able to create human kidney cells from human amniotic fluid stem cells combined with animal foetal kidney cells. The scientists now want to work out what signals are being passed between the two cell types to make them become kidneys, so they can achieve the same result using only human amniotic stem cells. “At the moment we throw amniotic fluid away when babies are born. But if we kept it and froze down the stem cells of everybody born in the UK, there would be cells that could build kidneys waiting for them, frozen, in case they ever needed them. “It wouldn't be that expensive. It sounds a bit like science fiction-like, but actually it's not. Freezing a few cells is cost-effective compared with the cost of keeping someone on dialysis for years,” Davies said.