One of the challenges of stem cells research has been to appease the ethical and moral controversies surrounding the use of stem cells. These specific concerns are usually related to embryonic and foetal stem cells because the harvesting of such stem cells does with most techniques, result in the destruction of an embryo. It is not, however, a simple case of simply using adult stem cells because embryonic stem cells have some notable advantages over adult stem cells.
Embryonic or Adult Stem Cells?
Despite the ethical controversies surrounding embryonic stem cell use, they tend to replicate more rapidly and they also have the ability to differentiate into many more cell types than adult stem cells. Furthermore, because these cells are ‘younger’ than adult stem cells, they do not usually have the genetic abnormalities that adult stem cells can develop over time.
Reprogramming Adult Stem Cells Into Embryonic Stem Cells
Several studies have been published from research performed in Japan. In the studies, adult stem cells were essentially ‘rewound’ and the differentiation process ran backwards, which caused the adult stem cells to revert into an embryonic stem cell like state. The cells were virtually identical to true embryonic stem cells as was the gene expression. The cells were also capable of becoming a fully functioning organism, which is a true ‘test’ of embryonic stem cells. Previously, a study on mice had stated that it produced embryonic stem cells from adult stem cells. However, while these cells could develop into all tissue types, they could not produce a live animal, which indicated that the cells were really only partially reprogrammed. In a more recent study, however, cells were fully reprogrammed. By turning on the expression of four chemicals in the cells of an adult mouse, these cells were reprogrammed in reverse to an embryonic like state. Ultimately, the cells could not be distinguished from true embryonic stem cells. The greatest challenge will still be to produce these results in human cells. First, however, many other challenges will need to be overcome in studies before success with human cells can become a reality.
Unfortunately, the process itself is not without its challenges. It is a very inefficient process because only a handful of cells out of thousands can thus far be successfully reprogrammed. In addition, these reprogrammed cells can go on to develop abnormalities, which must be resolved before any treatments with the cells can become a reality. Another issue is that the four factors – or chemicals – used in studies on mice may not be the same factors that allow for reversion in human cells. A retrovirus was originally used to introduce the genes of each factor into the cells but such retroviruses can also activate genes that trigger tumour growth. All of these issues must be resolved before this particular process can become feasible for use on humans.
Still, the possibility to obtain the benefits of embryonic stem cells while originally using adult stem cells is exciting because it provides a way to appease the ethical concerns regarding the use of true embryonic stem cells. Until then, the controversy will still remain but continued research can hopefully provide treatments for disease that are acceptable to all members of the public.