The debate surrounding stem cell research is nothing new. For years, proponents of embryonic stem cell research, believing in the promise of stem cell therapies to combat human disease, have been battling for increases in funding. At the same time, opponents who find the use of stem cells from human embryos morally unacceptable have been pushing for increased restrictions. Recently, however, the heated polemic appears to be slowly dying down as more and more Americans are finding themselves in favor of embryonic stem cell research. The percentage of people who find stem cell research to be morally acceptable has increased by nearly ten percentage points since 2003. According to recent studies, 61% of Americans are in favor of expanding funding for embryonic stem cell research, and 51% of citizens even fear that America will fall behind in medical advances if the government does not fund embryonic stem cell research.
New advancements in adult stem cell research further reduced the controversy surrounding embryonic stem cell research. Adult stem cells and reprogrammed stem cells, or induced pluripotent stem cells, provided an alternative to using stem cells derived from human embryos. This approach was met with widespread support from Americans with diverse religious, political, and cultural backgrounds. Some of the staunchest opponents of embryonic stem cell research came out in support of adult stem cell research as a substitute for the research they found morally unacceptable. In 2006, Pope Benedict XVI openly endorsed research using adult stem cells and the Vatican now hosts yearly conferences on the subject. Adult stem cell research provided a happy intermediate in which researchers could make use of the powerful ability of stem cells to multiply and become many different cell types without the controversial destruction of human embryos.
Just as the debate seemed to be drawing to a close, however, a groundbreaking announcement from Vienna last month has the potential to put a new face on the stem cell dispute. Researchers at the Institute of Molecular Biotechnology of the Austrian Academy of Sciences revealed that they had been able to grow 3D “mini brains” from a mixture of stem cells and chemical signals. These brains, or cerebral organoids, do notpossess all the cell types, compartmentalization, or function of a fully formed adult brain but do accurately recreate certain aspects of mammalian brain development. The group went on to show that their cerebral organoids could be used to model neurological disorders by creating an organoid model of the disease microcephaly. Microcephaly results in smaller than average brain size, and the research team used induced pluripotent stem cells from a patient with the disease to mimic it in organoid culture.
While many are excited about the prospect of using the mini brain model to study the development of neural diseases, some are concerned about where this line of research may lead. Scientists are a long way off from producing full-sized, functioning brains; however, there is likely to be quite a debate as to whether this should be allowed tohappen in the future. Since the brain is the seat of our intelligence and the emotion and control center for the rest of our bodies, many feel that we are our brains. What is the ethical significance, then, of artificially synthesizing brains in a laboratory? While it is widely agreed upon that cloning an entire human is morally wrong, does the same logic apply to the cloning of our brains?
With these advancements, we may see the source of controversy shift from the utilization of stem cells to the purpose for which they are being used. The heart of the debate surrounding the destruction of embryos in order to obtain stem cells centered on the question of when an embryo is considered alive. Now, the same question can be applied to when a “cerebral organoid” is considered to be alive. At what point in the development of these brains do neuronal synapses and signaling constitute real thinking? And if these brains are capable of a primitive form of thought, is it ethically sound to not only create these models but to also manipulate them for the study of disease? Questions such as these will lead to a new field of ethics with no clear opinions dictated by party or religion, as such questions have never been relevant before the recent advancements in stem cell biology.
Rebecca Marton is a senior Biological Sciences major at the University of Notre Dame and co-Editor in Chief of Scientia, the undergraduate journal of research for Notre Dame’s College of Science. She studies retinal regeneration in the adult zebrafish and plans to pursue a Ph.D. in stem cell biology.