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Scientists in kidney donor organ breakthrough
& I1 i. V5 v# m7 t# J: o8 jLyndsay Moss - Scotland on Sunday - 10th April 2011
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Scottish scientists have succeeded in growing kidneys in a laboratory in a breakthrough that could help tackle the tragic shortage of organs for transplant.
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Researchers at the University of Edinburgh created the organs by manipulating stem cells – early cells which are the building blocks of the body – to form the structure of a kidney.
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9 J+ n* b5 N" D' [5 H9 f3 iThe scientists then managed to create kidneys which measure just half a centimetre in length – the same size as a kidney in a foetus. They hope the tiny kidneys will be able to grow to maturity after being transplanted into patients' bodies.
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The kidneys were grown in the laboratory using a combination of cells from amniotic fluid – the fluid which surrounds all babies in the womb – and animal foetal cells in a breakthrough to be outlined at the city's Science Festival later this month.
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V- ]. q5 B8 p. j6 g% }The technique holds out the prospect of scientists being able to collect amniotic fluid at birth to be stored until needed at a later date if a patient develops kidney disease.
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( T+ `1 u Y8 Q7 c& f! i. c+ ^- q g) OThe patient's own amniotic fluid cells can then be used as the base for creating a new kidney., _( n. Q O$ q4 [7 S+ r. d
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Using the patient's own cells will, in theory, also end the problem of rejection that arises when an organ from a deceased donor is used.$ b u ?5 L% G" e
) i/ C9 `3 {9 }! YAlmost 7,000 people in the UK are currently on the waiting list for a new kidney, and demand for the organs is expected to grow as the average life expectancy increases./ q' M. K: E6 ^& @
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Patients' groups describe the use of stem cell technology as the "holy grail" that promises to reduce the shortage of several types of organs.$ [/ ?" @2 n& m' @% C M
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Last week, Japanese scientists managed to "grow" a retina in the laboratory from stem cells for the first time, while American researchers announced that artificial hearts, also created from stem cells, could be beating within weeks.
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The Edinburgh researchers are at the forefront of a global attempt to use stem cells culled from amniotic fluid to create new human kidneys.
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Physiologist Jamie Davies, a professor of experimental anatomy at the university, 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 is a long way from being a beautifully, anatomically organised organ like a kidney which is quite a complicated structure. So we are working on how you turn cells floating about in liquid into something as precisely arranged as a kidney.
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- x- K$ {4 F) v; w- }- _7 T& @"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."
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/ ] y! M$ E1 L' L7 WTo 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.
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5 t( x: x% x) L2 d( _3 t3 {A team in Michigan has taken embryonic stem cells and manipulated them, using chemicals, to become kidney stem cells.: Q; A k0 t/ \1 Y1 p& m
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Using a related technique, the scientists in Edinburgh, working with colleagues in Austria, were able to create human kidney cells from human amniotic fluid stem cells combined with animal foetal kidney cells.4 C/ d* e) d2 V
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In a paper published last month in the journal Organogenesis, 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., A9 k* ^* M) i' t- b
; V8 N, }% ~, TThe next challenge will be to transplant the kidney into a human. . A team in St Louis in the US has already shown that it is possible to transplant a foetal kidney into an adult animal and for it to grow and function properly.
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9 K4 Q% U! K+ Q' |! U6 g) MDavies predicts that the technology could be ready for testing in humans in around ten years. Researchers hope to be able to use a patient's own cells, to reduce the risk of an organ being rejected.6 Q1 y1 J2 K7 {: S; [4 @3 t
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This would involve perfecting the technique to use cells from amniotic fluid collected at birth. "We already know that stem cells that come from amniotic fluid are quite good at making kidneys," Davies said.
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"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.
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"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."8 }& ~2 Q) x9 k( D& {& T6 Z0 D
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After growing a bespoke kidney in the laboratory, the organ could then be implanted in a patient's body and allowed to grow for a year or more before it was able to take on the functions of the kidney.
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Tim Statham, the chief executive of the National Kidney Federation, described the research as "very exciting".
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"We have a policy to encourage stem cell research because for us it is the holy grail," he said. "We have a desperate shortage of both living organs and deceased organs. There simply are not enough to go around and every year 3,000 kidney patients die on dialysis, of whom 400 are on the kidney transplant waiting list."
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发表于 2011-4-14 15:40
