Stem cells have become a popular topic not only in the scientific community, but also within the political realm. There is much debate whether embryonic stem cells, stem cells derived from embryos, should be allowed United States federal funding. Much of the debate stems from pro-life organizations, which condemn abortion, because extracting stem cells from an embryo will inevitably kill the embryo as well. The scientific community argues stem cells have the hope to cure diseases such as Alzheimer's disease and even Leukemia. From the readers' perspective, the issue seemingly has no hope for a compromise because like abortion, there is no answer but another religious debate. However, there are many different types of stem cells, or progenitor cells and not all of them arise from embryos.
In an adult human, there are quite a number of progenitor cells that act like embryonic stem cells. The cells are able to differentiate, or become a number of other cell types. Another word for these cells is multipotent, which means they can become certain cells, like blood cells, but cannot become any cell in the body like embryonic stem cells can. For example, bone marrow carries haematopoietic stem cells, which are multi-potent cells that can turn into a variety of different blood cell types, such as white blood cells and platelets. Recently, researchers have found stem cells in the human adult brain, which can become different types of neuronal cells. Some researchers have also found these cells in the adult eye. However, the problem that arises from these progenitor cells is they are only multipotent and not totipotent cells. Therefore, they cannot turn into every cell type in the body as embryonic stem cells can.
Recently in the news, scientists were able to extract adult skin cells and could turn it into a “stem cell” by changing 4 genes of the cell. This is an important breakthrough because it would allow scientists to bypass the controversy over embryonic stem cells because it is derived from skin cells from an adult human. The downfall of this breakthrough is that one of the genes codes for tumors, and obviously we can't be treating people with cells that have the possibility to turn into a tumor. However, this is still far from clinical trials and by then hopefully scientists will uncover how to suppress the tumor-like properties.
A major flaw in human embryonic stem cell research is even if we are able to create these stem cells and transplant them effectively; we still have another huge obstacle to face. The obstacle is the human immune response. We face this problem today in medicine when we transplant organs from an organ donor. Some of you may have heard the phrase "the patient is rejecting the organ." The same thing will happen if we try to transplant embryonic stem cells into an adult. As long as the cells come from another person they will be rejected. In research animals are given immunosuppressants in order to ward off the auto immune response. So before we see embryonic stem cell transplants we must overcome this hurdle. If we were able to derive stem cells from the original person through adult stem cells it would ameliorate the issue.
As far as cures for the future, I believe it will be quite a while before we see human trials for stem cells because there is still much more to learn about them. Even if these cells are able to differentiate into any cell in the body and do not cause tumors or an autoimmune response we are still unsure how we can implement them safely into the body. But current research shows that there is much opportunity and definitely the possibility of curing diseases. So the question is still should we give federal funding to embryonic stem cell research and compete with the rest of the world that allows it, or should we focus more on adult human stem cells? You decide!
