This may be old news for some of you, but I was on vacation all last week and could not post anything about it until now. Two teams of scientists, one American and one Japanese, have independently discovered a way to revert adult cells into pluripotent form (functional equivalent to embryonic stem cells). This discovery will likely solve the moral dilemma posed by embryonic stem cell research. This is BIG news! See EurekAlert 1, EurekAlert 2, EurekAlert 3, EurekAlert 4, National Geographic News, BreitBart.com, BBC News 1, BBC News 2, MSNBC and and PhysOrg for sample media reports.
Scientists claim embryonic stem cells hold the greatest potential for cures because they are pluripotent (meaning they are able to turn into any one of the body’s 220 cells). The ethical problem with embryonic stem cell research (ESCR) is that to obtain ESCs, the embryo has to be killed. For this, and other practical reasons, alternative methods of obtaining embryonic stem cells have been sought.
What the two teams of scientists just discovered was a means of obtaining stem cells that possess all the characteristics of ESCs (such as pluripotency, indefinite self-renewal, etc.), without having to kill embryos to get them. In fact, this new method does not even involve the use of embryos.
To obtain the pluripotent cells scientists inserted a recipe of four genes (Oct3/4, Sox2, c-Myc and Klf4 in the Japanese study, and OCT4, SOX2, NANOG, and LIN28 in the American study) into adult skin cells (fibroblasts). These genes have the effect of reprogramming the skin cell so that it regresses back to its pluripotent state, becoming the functional (and nearly biological) equivalent of an embryonic stem cell. It de-differentiates the differentiated skin cells just as in cloning, but unlike cloning, the “product” is a pluripotent stem cell, not an embryo. This process is being called somatic cell reprogramming, or cell regression. The altered cells are being called “Induced Pluripotent Stem Cells,” or iPS.
Robert Lanza noted the significance of this breakthrough when he said, “It’s the holy grail. It’s like turning lead into gold.”
Not only is this method morally advantageous to ESCR, but it is practically advantageous as well. There are not enough surplus IVF embryos available for ESCR, and there is a lack of eggs for use in cloning new embryos (not to mention the fact that cloning is an additional moral concern, and has proved unfruitful to date). In contrast, somatic cell reprogramming is an easy process that is not dependent on embryos or donor eggs. We can reprogram as many skin stem cells as there are people with skin! Somatic cell reprogramming has the potential to give us an unlimited supply of pluripotent stem cells. Furthermore, unlike stem cells from surplus embryos, iPS cells are genetically identical to their donor, and thus pose no risk of rejection when inserted into their body.
There are still kinks to be worked out, namely, how to remove the copies of the four genes from the stem cell once they have done their job. “The crucial next step is to find a way to switch on the genes that cause the skin cells to regress into stem cells rather than relying on the retrovirus to insert the genes.” And of course, many of the same practical difficulties involved with the use of embryonic stem cells apply to iPS cells as well, such as their tendency to form tumors, and our lack of ability to control their differentiation. So this breakthrough brings us no closer to developing treatments and cures using pluripotent stem cells. The only stem cell treatments to date come from multipotent stem cells, more commonly referred to as adult stem cells.
Somatic cell reprogramming is so promising that even Ian Wilmut, creator of the somatic cell nucler transfer method of cloning, announced that he is abandoning therapeutic cloning in favor of cell regression. He said, “I am anticipating that before too long we will be able to use the Yamanaka approach to achieve the same, without making human embryos. I have no doubt that in the long term, direct reprogramming will be more productive, though we can’t be sure exactly when, next year or five years into the future.”
Now, the only reason to continue the pursuit of cloning embryos is if we want to birth them, or involve ourselves in genetic engineering of humans. Since those pressing for cloning were so adamant to denounce this “form” of cloning, it will be hard to make a case for it now. I’m sure some will continue to do so, however, because they want to genetically engineer humans, and birth clones. Others have financial interests in ESCR and cloning that are not easily disentangled. A lot of money was bet on ESCR and cloning, so a lot of people have a lot to lose. They will not let go of their money and their interests easily. We’ll have to wait and see how it all pans out.