日本干细胞研究或可实现用猪生成人类器官

xiaoqi

日本干细胞研究或可实现用猪生成人类器官
+ r  m( c4 G: Q& P( ]    北京时间6月23日消息，科学家发现，只要把一种干细胞注入到另一种动物的胚胎里，就能创造出拥有另一物种器官的嵌合体动物。也许通过这一发现，科学家能让猪长出人类器官，用来进行器官移植。
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    研究人员把家鼠的干细胞移植到小白鼠的胚胎里，于是诞生了长着家鼠器官的小白鼠。这些小白鼠已经经过转基因改造，不能产生自己的器官。这项技术最终将能利用患者的干细胞，让猪长出人类器官，用于器官移植。采用这种方法将能大大降低移植手术产生排异的风险。由于使用的是患者自己的干细胞，因此移植器官产生排异的可能性会被降至最小。除此以外，它还提供了充足的器官供应。
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     日本东京大学干细胞生物学和再生医学中心主管中内宏光(Nakauchi Hiromitsu)教授是这项研究的负责人，他说：“我们的最终目标是诱使多能干细胞产生人类器官。这项被称作囊胚互补的技术为我们提供了一种器官供应的全新方法。我们已经在家鼠和小白鼠之间进行了成功尝试。现在我们对利用这种方法生成功能性人类器官非常有信心。”诱导性多功能干细胞是一种成熟干细胞，它能从皮肤等任何单一组织中获取，用来生成任何类型的人体细胞。
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    中内宏光及其同事把从家鼠体内提取的这些细胞注射到不能长出自己的胰腺(这种器官能产生胰岛素等多种重要激素)的小白鼠的晶胚里。小白鼠到了成年期后，它们并未表现出糖尿病迹象，因为它们已经形成一个胰腺，这个胰腺几乎完全是由注射的家鼠干细胞形成的。研究人员称，小白鼠体内的家鼠干细胞形成了缺失的胰腺。如果利用人体干细胞重复这一试验，通过这项技术也许能够替换糖尿病患者的胰腺，治好糖尿病。
2 B" [  F( B' V" GScience News
' Q& ?, Z5 v6 o; k) I3 yPigs could grow human organs in stem cell breakthrough
" S5 e$ s6 q+ }1 ]Human organs could be grown inside pigs for use in transplant operations following research using stem cells.
: s1 F5 Z6 e- KScientists have found they can create chimeric animals that have organs belonging to another species by injecting stem cells into the embryo of another species. * v: O2 B: m8 h! z6 o
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The researchers injected stem cells from rats into the embryos of mice that had been genetically altered so they could not produce their own organs, creating mice that had rat organs.
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The researchers say the technique could allow pigs to grow human organs from patient's stem cells for use as transplants. / N) S3 w( o9 G7 i1 S
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By using a patient's own stem cells it could help to reduce the risk of the transplanted organ being rejected while also providing a plentiful supply of donor organs.
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, E/ d: e1 v6 T$ U% I7 RCurrent organ shortages mean that patients must endure long waiting lists for transplants. # H' A2 K  T0 R! }/ }8 }2 K/ B- Z$ y
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Professor Hiromitsu Nakauchi, director of the centre for stem cell biology and regenerative medicine at the University of Tokyo in Japan and who led the research, said: "Our ultimate goal is to generate human organs from induced pluripotent stem cells.
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: a" o( [, f* n* S% s, ~"The technique, called blastocyst complementation, provides us with a novel approach for organ supply. We have successfully tried it between mice and rats. We are now rather confident in generating functional human organs using this approach." ' J/ v) T6 W( P1 L0 y" I. ^

0 R; b& p. ?8 h6 b( v4 lProfessor Nakauchi, who presented the study at the annual conference of the European Society of Human Genetics, used a type of adult stem cell known as induced pluripotent stem cells, which can be taken from a sample of tissue such as the skin and encouraged to grow into any type of cell found in the body. * o% T& c6 ?8 K% \

6 Z1 g+ A3 C( S% G) v6 pTogether with his colleagues, he injected these cells taken from rats into the embryos, or blastocysts as they can be called, of mice that were unable to grow their on pancreas, the organ that produces important hormones including insulin.
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- c, v; }9 t( c8 k0 i7 y3 e1 NWhen the mice matured to adulthood, they showed no signs of diabetes and had developed a pancreas that was almost entirely formed from the injected rat stem cells. ' ?( E9 Y, A% b+ V1 ~
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The scientists claim the rat stem cells grew in the niche left by the absent mouse pancreas and so almost any organ could be produced in this way.
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If replicated using human stem cells, the technique could produce a way of treating diabetic patients by providing a way of replacing their pancreas. 9 w7 D" }3 G7 @9 s8 i; a

, W* |& G, L% b  g$ @! \' pThe project has echoes of the bestselling book and film Never Let Me Go where clones are used to provide organ donations for the wealthy. In reality researchers are not allowed to create human embryos that lack the ability to grow organs and so they hope to do the same using pigs. 9 \9 e2 H9 f8 v) {

  _4 ^$ i. e( W( EProfessor Nakauchi said they hoped to further test the technique by growing other organs and were also seeking permission to use human stem cells.
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; z, _2 S& A/ s" TThey have, however, already managed to produce pigs that were able to generate human blood by injecting blood stem cells from humans into pig foetuses. " D6 Q/ O& |$ G6 q
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He said: "For ethical reasons we cannot make an organ deficient human embryo and use it for blastocyst complementation. , N+ W( A- X& `4 D0 d

0 E: Z2 r# ^3 y/ M"So to make use of this system to generate human organs, we must use this technique using blastocysts of livestock animals such as pigs instead. ' D8 ?4 {! S$ M) A& o9 f
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"Blastocyst complementation across species had never been tested before, but we have now shown that it can work."
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  {) L" A' m! ]8 p1 ]Professor Chris Mason, chair of regenerative medicine at University College London, said: "There is no doubt that curing diabetes is challenging, but this could be a potential way forward albeit a very long shot requiring sustained resources and major finance for its testing and development."   N. t( L; J. R7 G" P) k

% N5 r, `# p- n' K: L$ G' d"For something like a kidney transplant where it is not urgent, it would be highly attractive to be able to take cells from a patient, grow them in this way and deliver a personalised kidney." ( C+ ?% H4 ]- Y. y
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"There is a long way to go before it could result in useable transplants, but it is an exciting vision."
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