Better Method for Creating Embryonic Stem Cell Lines
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Mignon: By plucking single cells from human embryos, Robert Lanza from Advanced Cell Technologies in Massachusetts and his colleagues have been able to generate new lines of cultured human embryonic stem (ES) cells while leaving the embryo intact. The research, which was published this week in the journal Nature, could allow scientists to pursue human ES cell studies but avoid the controversial destruction of human embryos.
Embryonic stem cells are typically grown by extracting a mass of cells from an embryo after it forms a hollow blastocyst, destroying the embryo in the process. But last year, Lanza’s team showed that they could instead remove a single cell from an earlier stage mouse embryo and amplify it into a colony of ES cells in culture. This procedure is similar to that used during in vitro fertilization (IVF) to remove a single cell for preimplantation genetic diagnosis.
In the following clip, Lanza describes his findings to Chris Smith of the Nature podcast.
Lanza: We have shown that we can not only generate stem cells without destroying the embryo, but that the remaining embryo also has the potential to go on and create a healthy blastocyst.
Smith: How is that achieved?
Lanza: What we're actually doing is removing a single cell form an eight-cell stage embryo, and then we actually culture that cell in the petri dish and are actually able through various manipulations to create stable embryonic stem cell lines.
Smith: Are you satisfied that the cells you generated are pretty much normal, in other words they have normal genotypic and phenotypic characteristics?
Lanza: Yes, it appears as thought these cells are absolutely identical to all the other human embryonic stem cell lines we have in the laboratory, including the so called presidential stem cell lines. They differentiate into all three germ layers, they are totally normal karyotypically, and they also are able to turn into the different germ layers in both teratomas and embryoic bodies, and through various other techniques that we have studied, in fact, we've been able to turn theses into endothelial cells, into vascular structures, into retinal pigment epithelium...they appear to be absolutely normal in all respects.
Smith: Do they appease President Bush's objection to the fact that you're destroying life to further life with traditional technology?
Lanza: Well, as you know the president objects to the fact that you would be sacrificing one life to save another, and in this instance there is no harm to the embryo that we are biopsying.
Smith: And the fact that you say that this could be used as a useful source of stem cells in order to repair individual in the future, but not everybody is going to have PGD done, are they though?
Lanza: This is correct, but important thing about embryonic stem cells is that they are immortal. So that if you generate even a few dozen lines, those lines are immortal and would allow us to proceed into the clinical for instance using the lines that had not been exposed to mouse feeders, and using the newer technique.
So, I think the goal here is to generate the lines that everyone would be comfortable with. That at least here in the U.S. would be eligible for federal funding, and then of course there are people who would prefer to actually use lines that may have been created without destroying the embryo.
Smith: So when will you be able to test these cells formally, and check out their clinical potential?
Lanza: Well, we've already done this, at least preclinically, we've tested these cells in various animal models and shown that the differentiated replacement cells that we have generated are actually functional, and again we have also studied these in terms of all the various markers and shown that these cells appear to be normal in all respects.
Mignon: Again, thank you to Nature magazine at www.nature.com for providing that audio clip.
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