新奇：头上钻孔移植细胞补大脑
路透社伦敦消息 致力于开发新型脑修复技术的科学家们都期望，在将来的某一天，医生只需在局麻下给病人的颅骨钻一个小孔，用一个充满大量可以繁殖细胞的注射器就可修复受损伤的脑组织。这种大胆的设想为那些被中风或脑退行性疾病，如老年痴呆病或帕金森氏病困扰的病人带来了希望。然而，专家们认为要证明这种方法的安全性和有效性尚需数年时间。
目前已有越来越多的公司试图将这种技术商业化，其中包括英国的神经元再生公司(ReNeuron)，这是英国精神病学研究院属下的一家公司，已经计划在伦敦选择性投资市场上通过出售其所持证券融资2千2百万到2千9百万美元。该公司利用流产胎儿组织培养的神经干细胞来重建受损的脑组织。干细胞是“基细胞”，能分化形成体内多种组织细胞。这一理论已在大鼠实验中得到证实，计划在今年下半年就开始进行人体试验。
向受损的脑组织移植细胞的想法并不是全新思维。在最近10年，医生们就一直在利用流产胎儿脑细胞移植来治疗一小部份帕金森氏病患者。这项技术是由瑞士伦德大学的科学家首先开创的，并且已证明可缓解帕金森氏病最严重的症状。但是，治疗一个成年人平均需要六个胎儿的脑组织，这使这项技术面临着临床应用和伦理学的双重难题。
, http://www.100md.com
神经元再生公司并不是涉足这一领域的唯一公司，目前在美国至少还有另外五家公司从事这一领域的研究开发，它们拥有最先进的技术。各大生物技术公司认为他们已经发现了解决脑组织来源问题的方法，而其中一种被神经元再生公司和其它几家公司采用的方法，就是利用遗传工程技术来“保存”人类细胞系，然后在试验室大量复制。另外一个途径是利用动物组织。
在临床试验方面，美国戴尔克瑞(Diacrin)公司遥遥领先于它的对手，已经可以从猪的胚胎提取可植入人体的脑细胞。虽然在去年早些时候，由于2例中风病人在治疗后发生并发症，该公司的研究遇到了挫折，但是产品的研发仍然在进行，而且该公司同时还在研究利用猪细胞治疗脊髓损伤和修复受损的心肌。
许多医生对将动物器官移植给人持保留意见，一些人预测这会传播未知的病毒，因此该领域的其它公司研究的重点是人体组织的移植，包括美国斯德塞尔斯公司(StemCells Inc.)和未上市的纽尔斯德生物药品有限公司(NeuralStem Biopharmaceuticals Ltd.)，以及英国私营公司塞尔费德斯公司(CellFactors)。塞尔费德斯公司在研究大量生产特殊类型的脑细胞，而前两家公司与神经元再生公司一样在从事干细胞的研究工作。
, 百拇医药
目前，医生们最近对越来越多的、脑组织具有自身修复能力的迹象感兴趣，例如，在一些因脑卒中死亡的婴儿中发现脑组织奇迹般地自己修复了。细胞植入可能最终使这种修复途径在成年人成为可能。但是英国卒中协会主任欧文·雷达汉(Owen Redahan)说，仍然有很多理论有待证实。虽然这种现象很有趣，但是要让卒中后受损的细胞恢复功能却是一件极其复杂的事情，可能需要上10年时间才能对它的可行性下结论。到目前为止的研究认为，无论是来源于人还是猪的脑细胞，都能成功移植以取代脑内损伤的细胞。但是，关键问题是能否精确恢复因原来的脑细胞死亡而尚失掉的脑功能。
神经元再生公司的董事长马丁·爱德华兹(Martin Edwards)也承认这项工作任重道远。他说：“尽管我们的某些竞争对手更加看好行情，并且认为在2004年或2005年前就可产生效益，但我不认为像我们这样的一个产品只需约8年的时间就可上市，因为必需进行的临床试验可能是长期的并且困难重重。”
Brain Repair Companies Sharpen Their Drills
, 百拇医药
LONDON (Reuters) - A local anesthetic, a small drill-hole in the skull and a syringe full of new cells may one day be all it takes to repair brain damage.
That, at least, is the hope of scientists pioneering a new kind of ``brain repair kit‘‘ using implants of mass-produced cells to patch up damaged gray matter.
The daring approach offers hope to those incapacitated by stroke or degenerative diseases such as Alzheimer‘s or Parkinson‘s. However, experts say it will take years before it is proven to be safe and effective.
, 百拇医药
A growing number of companies are lining up to commercialize the technology, including Britain‘s ReNeuron--a spin-off from the Institute of Psychiatry--which planned to raise $22 million to $29 million with its initial public offering on London‘s Alternative Investment Market this week.
ReNeuron uses neural stem cells, grown in culture from aborted fetus tissue, to regenerate damaged parts of the brain. Stem cells are ``master‘‘ cells that can be coaxed into forming many types of tissue in the body.
, 百拇医药
It has proven the principle in rats and plans to start trials on humans in the second half of next year.
ReNeuron is not alone. At least five other companies are operating in the field, with the most advanced work to date done in the United States.
The idea of transplanting cells into damaged brains is not altogether new.
For the last 10 years, doctors have been treating a handful of Parkinson‘s disease patients using cells transplanted from the brains of aborted fetuses. The technique, pioneered by scientists at Sweden‘s Lund University, has been shown to alleviate the worst symptoms of the disease.
, 百拇医药
But it takes an average of six fetuses to treat an adult brain, making the process practically--and ethically--problematic.
Biotechnology companies believe they have now found ways round this supply problem.
One option, being pursued by ReNeuron and several others, is to use genetic engineering to ``immortalize‘‘ human cell lines, which can then be produced indefinitely in the laboratory.
Implanted Pig Cells
, http://www.100md.com
Another approach is to turn to animal tissue.
US company Diacrin, which is more advanced than its rivals in terms of clinical trials, harvests brain cells from the fetuses of pigs for implant into humans.
Its research suffered a setback earlier this year after two cases of complications in stroke patients. But product development is continuing and Diacrin is also investigating using pig cells to treat spinal cord injury and to repair damaged heart muscle.
, 百拇医药
Nevertheless, many medics have reservations about animal-to-human transplants--with some speculating they might spread unknown viruses--and other firms in the field are concentrating on human tissue.
They include the privately owned US company Layton BioScience, which reported two months ago that it had successfully treated stroke patients using human cancer cells that had been ``retrained‘‘ to become nerve cells.
Among others in the field are US companies StemCells Inc. and unlisted NeuralStem Biopharmaceuticals Ltd., together with the private British firm CellFactors.
, http://www.100md.com
The two US firms, like ReNeuron, are working with stem cells while CellFactors is studying the mass-production of specific brain cell types.
Doctors have recently been intrigued by growing evidence of the brain‘s ability to repair itself, as demonstrated, for example, by dramatic recoveries in some infant stroke victims.
Cell implants might eventually make that kind of a recovery routine for adults.
, 百拇医药
Great Deal To Prove
But Owen Redahan, director of Britain‘s Stroke Association, says there is still a great deal to prove.
``The principle is interesting but it‘s going to be extremely complicated to get the cells to take over functions that have been destroyed after a stroke,‘‘ he said.
``I think it will take up to 10 years before we can say whether or not it is really possible.‘‘
, http://www.100md.com
Research so far suggests that cells--whether human or porcine--can be transplanted successfully to replace damaged ones. But the big question is whether the brain functions that died when the original brain cells died are replicated precisely, Redahan said.
Martin Edwards, chief executive of ReNeuron, admits it will be a long haul.
``I don‘t think a product like ours will be on the market for about eight years because the clinical trials required are likely to be long and quite difficult, although some of our competitors are far more bullish and talk of something by 2004 or 2005,‘‘ he said., 百拇医药
目前已有越来越多的公司试图将这种技术商业化，其中包括英国的神经元再生公司(ReNeuron)，这是英国精神病学研究院属下的一家公司，已经计划在伦敦选择性投资市场上通过出售其所持证券融资2千2百万到2千9百万美元。该公司利用流产胎儿组织培养的神经干细胞来重建受损的脑组织。干细胞是“基细胞”，能分化形成体内多种组织细胞。这一理论已在大鼠实验中得到证实，计划在今年下半年就开始进行人体试验。
向受损的脑组织移植细胞的想法并不是全新思维。在最近10年，医生们就一直在利用流产胎儿脑细胞移植来治疗一小部份帕金森氏病患者。这项技术是由瑞士伦德大学的科学家首先开创的，并且已证明可缓解帕金森氏病最严重的症状。但是，治疗一个成年人平均需要六个胎儿的脑组织，这使这项技术面临着临床应用和伦理学的双重难题。
, http://www.100md.com
神经元再生公司并不是涉足这一领域的唯一公司，目前在美国至少还有另外五家公司从事这一领域的研究开发，它们拥有最先进的技术。各大生物技术公司认为他们已经发现了解决脑组织来源问题的方法，而其中一种被神经元再生公司和其它几家公司采用的方法，就是利用遗传工程技术来“保存”人类细胞系，然后在试验室大量复制。另外一个途径是利用动物组织。
在临床试验方面，美国戴尔克瑞(Diacrin)公司遥遥领先于它的对手，已经可以从猪的胚胎提取可植入人体的脑细胞。虽然在去年早些时候，由于2例中风病人在治疗后发生并发症，该公司的研究遇到了挫折，但是产品的研发仍然在进行，而且该公司同时还在研究利用猪细胞治疗脊髓损伤和修复受损的心肌。
许多医生对将动物器官移植给人持保留意见，一些人预测这会传播未知的病毒，因此该领域的其它公司研究的重点是人体组织的移植，包括美国斯德塞尔斯公司(StemCells Inc.)和未上市的纽尔斯德生物药品有限公司(NeuralStem Biopharmaceuticals Ltd.)，以及英国私营公司塞尔费德斯公司(CellFactors)。塞尔费德斯公司在研究大量生产特殊类型的脑细胞，而前两家公司与神经元再生公司一样在从事干细胞的研究工作。
, 百拇医药
目前，医生们最近对越来越多的、脑组织具有自身修复能力的迹象感兴趣，例如，在一些因脑卒中死亡的婴儿中发现脑组织奇迹般地自己修复了。细胞植入可能最终使这种修复途径在成年人成为可能。但是英国卒中协会主任欧文·雷达汉(Owen Redahan)说，仍然有很多理论有待证实。虽然这种现象很有趣，但是要让卒中后受损的细胞恢复功能却是一件极其复杂的事情，可能需要上10年时间才能对它的可行性下结论。到目前为止的研究认为，无论是来源于人还是猪的脑细胞，都能成功移植以取代脑内损伤的细胞。但是，关键问题是能否精确恢复因原来的脑细胞死亡而尚失掉的脑功能。
神经元再生公司的董事长马丁·爱德华兹(Martin Edwards)也承认这项工作任重道远。他说：“尽管我们的某些竞争对手更加看好行情，并且认为在2004年或2005年前就可产生效益，但我不认为像我们这样的一个产品只需约8年的时间就可上市，因为必需进行的临床试验可能是长期的并且困难重重。”
Brain Repair Companies Sharpen Their Drills
, 百拇医药
LONDON (Reuters) - A local anesthetic, a small drill-hole in the skull and a syringe full of new cells may one day be all it takes to repair brain damage.
That, at least, is the hope of scientists pioneering a new kind of ``brain repair kit‘‘ using implants of mass-produced cells to patch up damaged gray matter.
The daring approach offers hope to those incapacitated by stroke or degenerative diseases such as Alzheimer‘s or Parkinson‘s. However, experts say it will take years before it is proven to be safe and effective.
, 百拇医药
A growing number of companies are lining up to commercialize the technology, including Britain‘s ReNeuron--a spin-off from the Institute of Psychiatry--which planned to raise $22 million to $29 million with its initial public offering on London‘s Alternative Investment Market this week.
ReNeuron uses neural stem cells, grown in culture from aborted fetus tissue, to regenerate damaged parts of the brain. Stem cells are ``master‘‘ cells that can be coaxed into forming many types of tissue in the body.
, 百拇医药
It has proven the principle in rats and plans to start trials on humans in the second half of next year.
ReNeuron is not alone. At least five other companies are operating in the field, with the most advanced work to date done in the United States.
The idea of transplanting cells into damaged brains is not altogether new.
For the last 10 years, doctors have been treating a handful of Parkinson‘s disease patients using cells transplanted from the brains of aborted fetuses. The technique, pioneered by scientists at Sweden‘s Lund University, has been shown to alleviate the worst symptoms of the disease.
, 百拇医药
But it takes an average of six fetuses to treat an adult brain, making the process practically--and ethically--problematic.
Biotechnology companies believe they have now found ways round this supply problem.
One option, being pursued by ReNeuron and several others, is to use genetic engineering to ``immortalize‘‘ human cell lines, which can then be produced indefinitely in the laboratory.
Implanted Pig Cells
, http://www.100md.com
Another approach is to turn to animal tissue.
US company Diacrin, which is more advanced than its rivals in terms of clinical trials, harvests brain cells from the fetuses of pigs for implant into humans.
Its research suffered a setback earlier this year after two cases of complications in stroke patients. But product development is continuing and Diacrin is also investigating using pig cells to treat spinal cord injury and to repair damaged heart muscle.
, 百拇医药
Nevertheless, many medics have reservations about animal-to-human transplants--with some speculating they might spread unknown viruses--and other firms in the field are concentrating on human tissue.
They include the privately owned US company Layton BioScience, which reported two months ago that it had successfully treated stroke patients using human cancer cells that had been ``retrained‘‘ to become nerve cells.
Among others in the field are US companies StemCells Inc. and unlisted NeuralStem Biopharmaceuticals Ltd., together with the private British firm CellFactors.
, http://www.100md.com
The two US firms, like ReNeuron, are working with stem cells while CellFactors is studying the mass-production of specific brain cell types.
Doctors have recently been intrigued by growing evidence of the brain‘s ability to repair itself, as demonstrated, for example, by dramatic recoveries in some infant stroke victims.
Cell implants might eventually make that kind of a recovery routine for adults.
, 百拇医药
Great Deal To Prove
But Owen Redahan, director of Britain‘s Stroke Association, says there is still a great deal to prove.
``The principle is interesting but it‘s going to be extremely complicated to get the cells to take over functions that have been destroyed after a stroke,‘‘ he said.
``I think it will take up to 10 years before we can say whether or not it is really possible.‘‘
, http://www.100md.com
Research so far suggests that cells--whether human or porcine--can be transplanted successfully to replace damaged ones. But the big question is whether the brain functions that died when the original brain cells died are replicated precisely, Redahan said.
Martin Edwards, chief executive of ReNeuron, admits it will be a long haul.
``I don‘t think a product like ours will be on the market for about eight years because the clinical trials required are likely to be long and quite difficult, although some of our competitors are far more bullish and talk of something by 2004 or 2005,‘‘ he said., 百拇医药