There has been a lot of talk about Dr. Yamanaka and his work on induced pluripotent stem cells (iPSCs) since he won the Nobel Prize earlier this week. There have even been some rumblings that pro-lifers should not be so happy about iPSCs since they are not “100% pro-life.”
Before I list the objections that some pro-lifers are having with this new technology, let me give you a quick refresher on what iPSCs are and how they are made. Pluripotent cells are cells that can become most or all of the 200 cell types of the body, but they cannot become other tissues like placenta. So pluripotent cells, alone without further manipulation, cannot implant and grow into a fetus, baby etc.
Before Dr. Yamanaka’s work, scientists would get pluripotent stem cells from the inner stem cell mass of an embryo. Dr. Yamanaka, realizing that we cannot continue to destroy embryos for stem cells, envisioned a way to reprogram an adult cell back to a pluripotent state. Yamanaka used a virus to deliver pieces of genetic material into an adult cell that “rebooted” that cell back to pluripotency so it can be coaxed into becoming another of the body’s cell types. Now scientists can take a skin cell, reprogram it and then grow lung tissue, neurons, or other tissue they want to study. Induced pluripotent stem cells are an alternative to cloning because you get stem cells that are a genetic match to a patient, but without creating and destroying a cloned human embryo.
So what are some of the pro-life objections I have been reading? First, there is a concern that iPSCs are dangerous because it is possible they can be used for cloning purposes. This concern stems from work where scientists, testing the pluripotency of the cells, were able to grow a mouse from just iPSCs suggesting that induced pluripotent stem cells are just like cloning, on their own able to produce a human being. But looking closer you find that the scientists had to manipulate some of the iPSCs with something called tetraploid complementation, so that the iPSCs could become the extra-embryo tissues like placenta. So while cloning creates a complete human embryo capable, at least some percentage of the time, of implanting in a uterus and continuing to grow, reprogramming adult cells back to pluripotency (upon my reading) only creates stem cells, not a complete organism.
Second, there is an objection that the viruses used for the reprogramming were grown in a cell-line called HEK 293. Cell line HEK 293 was derived from the kidney tissue of a boy aborted in the 1970s. HEK stands for “human embryonic kidney.” The HEK 293 line was subsequently genetically engineered with viral DNA and is now available for sale from a common chemical supply. While I have never personally worked with HEK 293, I understand that this cell line is commonly used just about everywhere — which does not negate the ethical implications, but does shed some light on why HEK 293 was used in developing iPSCs.
The objection of course is that by using HEK 293 to grow virus used in the technique, all iPSC research is morally tainted. To some extent that is true for early research, but scientists are getting away from using viruses for the reprogramming, so iPSC research can be free of this particular stain.
Analogously, vaccinations are commonly grown in 2 cell lines derived decades ago from aborted fetuses. Since no new abortions are needed to keep these cell lines going and vaccines are generally seen as vastly improving public health, Catholics can vaccinate their children if they ask for alternatives and voice their objections.
It is my opinion that the same applies here. I object to the use of HEK 293 for research period. Please, scientists, find a suitable alternative. That being said, it is possible that iPSCs in the future can be free from any moral taint coming from DNA or cell lines derived from illicit origin.
Another objection is the iPSCs are just like embryonic stem cells and so are no good for treating patients. It is true that because iPSCs are pluripotent like embryonic stem cells they will likely have many of the same safety issues for transplantation. More research is needed. What iPSCs are good for is creating model tissues for scientists to use to study disease progression and treatment.
As I have written before, previous to iPSCs, scientists would have to create a mouse or other animal that exhibited the symptoms of a human disease that they were interested in studying. Now they can take a skin cell from a person with a disease, reprogram that cell back to a pluripotent state, and then differentiate them into cells of interest whether they be neurons or fat cells. iPSCs can continue to grow in culture and be frozen giving researchers a nearly limitless supply of diseased cells to work on. This is especially useful in brain disorders because isolating neurons from the brain of a patient is dangerous. Scientists can use the iPSCs to generate tissue used for testing new drugs or other methodologies in the fight against disease.
Another objection is that iPSCs have been used to generate gametes for IVF in animal models. This is true. Scientists have created mouse egg and sperm with this technology and then used them to create mice. Some pundits are talking about using this technique to allow gay couples to have genetically related children. I see this as a problem not with iPSC technology per se, but as a problem with the fertility industry that has an anything goes attitude toward procreation. Get the fertility industry under control with some regulations prohibiting genetically modifying or manipulating gametes and embryos and this objection evaporates.
Stepping back and looking at the big picture, iPSCs, I believe, are something pro-lifes can be happy about with the knowledge that their history is not perfect. But remember that before iPSC technology, the talk was of nothing other than destroying IVF embryos and creating and destroying embryos through cloning as the “best” ways to develop stem cell cures. Now we have an alternative, developed directly as a way to avoid creating and destroying embryos. Which is why moral theologian Father Thomas Berg praised the work of Dr. Yamanaka for helping to “put human embryonic stem-cell research largely out of business.”
I think that is reason to celebrate.
