非转基因技术重编程羊水干细胞（附原文）
[i=s] 本帖最后由 细胞海洋 于 2012-7-8 22:35 编辑 [/i]研究人员用丙戊酸将羊水细胞重编程到更原始的状态，成为胚胎干细胞理想的替代来源。
[align=center][b]Amniotic Fluid Yields Alternatives to Embryonic Stem Cells[/b][/align]
ScienceDaily (July 3, 2012) — Stem cells found in amniotic fluid can be transformed into a more versatile state similar to embryonic stem cells, according to a study published July 3 in the journal Molecular Therapy. Scientists from Imperial College London and the UCL Institute of Child Health succeeded in reprogramming amniotic fluid cells without having to introduce extra genes. The findings raise the possibility that stem cells derived from donated amniotic fluid could be stored in banks and used for therapies and in research, providing a viable alternative to the limited embryonic stem cells currently available.
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Amniotic fluid surrounds and nourishes the fetus in the womb. It can be extracted through the mother's abdomen using a needle in a process called amniocentesis, which is sometimes used to test for genetic diseases. The fluid contains stem cells that come from the fetus. These cells have a more limited capacity to develop into different cell types than stem cells in the embryo.
The researchers used stem cells from amniotic fluid donated by mothers undergoing amniocentesis for other purposes during the first trimester of pregnancy. The cells were grown on a gelatinous protein mixture in the lab and reprogrammed into a more primitive state by adding a drug called valproic acid to the culture medium. An extensive set of tests found that these reprogrammed cells have characteristics very similar to embryonic stem cells, which are capable of developing into any cell type in the body -- a property known as pluripotency.
Even after growing in culture for some time, the reprogrammed cells were able to develop into functioning cells of many different types, including liver, bone and nerve cells. They also maintained their pluripotency even after being frozen and rethawed.
The results suggest that stem cells derived from amniotic fluid could be used in treatments for a wide range of diseases. Donated cells could be stored in banks and used in treatments, as well as in disease research and drug screening. A previous study estimated that cells from 150 donors would provide a match for 38% of the population.
Alternatives to embryonic stem cells are keenly sought because of ethical concerns and limited availability of donor embryos. Previous research has shown that it is possible to make adult cells become pluripotent by introducing extra genes into the cells, often using viruses. However, the efficiency of the reprogramming is very low and there is a risk of problems such as tumours caused by disrupting the DNA. The new study is the first to induce pluripotency in human cells without using foreign genetic material. The pluripotent cells derived from amniotic fluid also showed some traits associated with embryonic stem cells that have not been found in induced pluripotent stem cells from other sources.
Amniocentesis is associated with a small risk of causing a miscarriage, estimated to be about one in 100.
Dr Pascale Guillot, from the Department of Surgery and Cancer at Imperial, said: "Amniotic fluid stem cells are intermediate between embryonic stem cells and adult stem cells. They have some potential to develop into different cell types but they are not pluripotent. We've shown that they can revert to being pluripotent just by adding a chemical reagent that modifies the configuration of the DNA so that genes that are expressed in the embryo get switched back on.
"These cells have a wide range of potential applications in treatments and in research. We are particularly interested in exploring their use in genetic diseases diagnosed early in life or other diseases such as cerebral palsy."
Dr Paolo De Coppi, from the UCL Institute of Child Health, who jointly led the study with Dr Guillot, said: "This study confirms that amniotic fluid is a good source of stem cells. The advantages of generating pluripotent cells without any genetic manipulation make them more likely to be used for therapy.
"At GOSH we have focused on building organs and tissues for the repair of congenital malformations, which are usually diagnosed during pregnancy. Finding the way of generating pluripotent cells from the fluid that surround the fetus in the womb move us one step further in the this direction."
The study was funded by the Genesis Research Trust, the Henry Smith Charity and Action Medical Research.
The children's charity Action Medical Research are funding the researchers to explore the therapeutic benefits of transplanting donated placental stem cells from healthy babies to babies with brittle bone disease.
Dr Caroline Johnston, Research Evaluation Manager with children's charity Action Medical Research said: "These new findings could be a step forward for treatments of a wide range of diseases that affect babies and children. We are proud of our history of funding medical breakthroughs and of our support for these researchers in their move towards life changing therapies."
[color=Red]3楼原文 感谢naturalkillerce 提供[/color] [b]回复 [url=forum.php?mod=redirect&goto=findpost&pid=674525&ptid=57872][color=Olive]sunsong7[/color] 的帖子[/url][/b]
[color=Black][b]丙戊酸能够诱导羊水干细胞为多能性干细胞[/b]
时间：2012-07-05 08:30:52 来源：生物无忧 作者：davidtower
在一项新研究中,在羊水中发现的干细胞能够转化为一种功能性更强的类似于胚胎干细胞的状态.来自英国伦敦帝国学院(Imperial College London)和伦敦大学学院儿童健康研究所(UCL Institute of Child Health)的研究人员在不用引入外来基因的条件下成功地重编程羊水干细胞.这一发现有可能让人们把来自捐赠的羊水中的干细胞储存于干细胞库中,以及用于治疗和研究.相比于当前获得的数量有限的胚胎干细胞,这项研究为人们提供一种可行的替代性选择.相关研究结果于2012年7月3日在线发表在Molecular Therapy期刊上,论文标题为"Valproic Acid Confers Functional Pluripotency to Human Amniotic Fluid Stem Cells in a Transgene-free Approach".
羊水包围和滋养着子宫中的胎儿.它能够被人们利用羊膜穿刺术(amniocentesis)而从母亲的腹部中提取出.羊膜穿刺术导致流产的风险较小,经估计大约为1%.羊水含有来自胎儿的干细胞.相比于胚胎中的干细胞,这些干细胞发展为不同类型细胞的能力较为有限.
研究人员利用来自妊娠头三个月的母亲接受羊膜穿刺术之后捐赠的羊水中的干细胞开展研究.在实验室中,这些干细胞在胶状蛋白混合物上进行培养,接着在培养基中加入药物丙戊酸(valproic acid),它们就被重编程到一种更加原始的状态.经过广泛的各种各样的测试之后,研究人员发现这些重编程细胞具有非常类似于胚胎干细胞的特征,能够发展为体内任何类型的细胞---这一性质被称作多能性(pluripotency).
即便在体外培养一段时间之后,这些重编程细胞也能够发展为多种不同类型的功能性细胞,包括肝细胞、骨细胞和神经细胞.即便在经历冻存和解冻之后,它们也能维持它们的多能性.
这些结果提示着来自羊水的干细胞可能用于治疗多种疾病.来自捐献的羊水中的干细胞能够被储存在干细胞库中,用于临床治疗,以及用于疾病研究和药物筛选.
鉴于供体胚胎的伦理问题和数量有限,人们急切地寻求胚胎干细胞的替代物.以前的研究表明人们能够通过导入额外的基因到成体细胞中而让它们变成诱导性多能干细胞(induced pluripotent stem cells, iPSCs),并且经常是利用病毒来导入基因的.然而,这种重编程效方法的率非常低,而且还会产生诸如因破坏细胞DNA而导致肿瘤产生之类的风险.这项新研究是第一次无需导入外源遗传物质而诱导人类细胞产生多能性.将羊水干细胞重编程而产生的多能性细胞也表现出一些与胚胎干细胞相关联的但是在来自其他来源的iPSCs中没有发现的特征.
伦敦帝国学院外科与癌症部门研究员Pascale Guillot博士说,"羊水干细胞处于胚胎干细胞和成体干细胞之间.它们有一定的发展为不同类型细胞的潜能,但是它们不是多能性的.我们证实只需加入一种改变DNA构象的化学试剂从而让在胚胎中表达的基因重新开启,这样它们能够返回到多能性状态."
论文通信作者、伦敦大学学院儿童健康研究所研究员Paolo De Coppi博士说,"这项研究证实羊水是一个良好的干细胞来源.不需任何遗传操纵而产生多能性细胞的优势使得它们更可能用于治疗."[/color] [b]回复 [url=forum.php?mod=redirect&goto=findpost&pid=674525&ptid=57872][color=Olive]sunsong7[/color] 的帖子[/url][/b]
[b]回复 [url=forum.php?mod=redirect&goto=findpost&pid=674525&ptid=57872][color=Olive]sunsong7[/color] 的帖子[/url][/b]
Sounds another good news.
It seems we will have more, at least now three possible sources for harvesting the pluripotent SCs:
I, IPS, is the most complicated and with the risk of the formation of cancer in the use of the viruses in the inducing process.
II, SCs from the induced amniotic fluid cells with valproic acid are simplified extremely.
III, the SCs found from the placent can be harvested directly.
On the way of exploration we do need to be open-minded, but not stiff-necked.
[b]回复 [url=forum.php?mod=redirect&goto=findpost&pid=674525&ptid=57872][color=Olive]sunsong7[/color] 的帖子[/url][/b]
Sounds another good news.
It seems we will have more, at least now three possible sources for harvesting the pluripotent SCs:
I, IPS, is the most complicated and with the risk of the formation of cancer in the use of the viruses in the inducing process.
II, SCs from the induced amniotic fluid cells with valproic acid are simplified extremely.
III, the SCs found from the placent can be harvested directly.
On the way of the exploration we do need to be open-minded, but not stiff-necked.
:D &:( ，不知道能不能找到精原干细胞类似的....发现。 这个研究还是很有意思的, 因为羊水细胞自然离干细胞更近, 这个跟脐带血干细胞有异曲同工, 不过,应该用途更广,
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