Stem cell therapy
Most of the issues concerning uses of stem cells in the brain are the same as any of the bioethical or purely ethical questions you will find regarding the use and research of stem cells. The field of stem cell research is a very new field which poses many ethical questions concerning the allocation of stem cells as well as their possible uses. Since most stem cell research is still in its preliminary phase most of the neuroethical issues surrounding stem cells are the same as stem cell ethics in general.
More specifically, the way stem cell research has been involved in neuroscience is through the treatment of neurodegenerative diseases and brain tumors. In these cases, scientists are using neural stem cells to regenerate tissue and to be used as carriers for gene therapy. In general, neuroethics revolves around a cost-benefit approach to finding techniques and technologies that are most beneficial to patients. Progress in certain fields that has been shown to be beneficial when using stem cells to treat certain neurodegenerative diseases such as Parkinson’s disease.
A study done in 2011 showed that induced pluripotent stem cells (iPSCs) can be used to aid in Parkinson’s research and treatment. The cells can be used to study the progression of Parkinson’s as well as used in regenerative treatment. Animal studies have shown that the use of iPSCs can improve motor skills and dopamine release of test subjects with Parkinson’s. This study shows a positive outcome in the use of stem cells for neurological purposes.
In another study done in 2011 used stem cells to treat cerebral palsy. This study, however, was not as successful as the Parkinson’s treatment. In this case, stem cells were used to treat animal models who had been injured in a way that mimicked CP. This brings up a neuroethical issue of animal models used in science. Since most of their “diseases” are inflicted and do not occur naturally, they can not always be reliable examples of how a person with the actual disease would respond to treatment. The stem cells used did survive implantation but did not show significant nerve regeneration. However, studies are ongoing in this area.
As discussed, stem cells are used to treat degenerative diseases. One form of a degenerative disease that can occur in the brain as well as throughout the body is an autoimmune disease. Autoimmune diseases cause the body to “attack” its own cells and therefore destroys those cells as well as whatever functional purpose those cells have or contribute to. One form of an autoimmune disease that affects the central nervous system is multiple sclerosis. In this disease, the body attacks the glial cells that form myelin coats around the axons of neurons. This causes the nervous system to essentially “short circuit” and pass information very slowly. Stem cells therapy has been used to try to cure some of the damage caused by the body in MS. Hematopoietic stem cell transplantation has been used to try and cure MS patients by essentially “reprogramming” their immune system. The main risk encountered with this form of treatment is the possibility of rejection of the stem cells. If the hematopoietic stem cells can be harvested from the individual, risk of rejection is much lower. But, there can be the risk of those cells being programmed to induce MS. However, if the tissue is donated from another individual there is a high risk of rejection leading to possibly fatal toxicity in the recipient’s body. Considering that there are fairly good treatments for MS, the use of stem cells may have a higher cost than the benefits they produce. However, as research continues perhaps stem cells will truly become a viable treatment for MS as well as other autoimmune diseases.
These are just some examples of neurological diseases in which stem cell treatment has been researched. In general, the future looks promising for stem cell application in the field of neurology. However, possible complications lie in the overall ethics of stem cell use, possible recipient rejection, as well as over-proliferation of the cells causing possible brain tumors. Ongoing research will further contribute to the decision of whether stem cells should be used in the brain and whether their benefits truly outweigh their costs.
The primary ethical dilemma that is brought up in stem cell research is concerning the source of embryonic stem cells (hESCs). As the name states, hESCs come from embryos. To be more specific, they come from the inner cell mass of a blastosphere, which is the beginning stage of an embryo. However, that mass of cells could have the potential to give rise to human life, and therein lies the problem. Often, this argument leads back to a similar moral debate held around abortion. The question is: when does a mass of cells gain personhood and autonomy? Some individuals believe that an embryo is a person at the moment of conception and that using an embryo for anything other than creating a baby would essentially be killing the baby. On the other end of the spectrum, people argue that the small ball of cells at that point only has the potential to become a fetus and that potentiality, even in natural conception, is far from guaranteed. According to a study done by developmental biologists, between 75–80% of embryos created through intercourse are naturally lost before they can become fetuses. This debate is not one that has a right or wrong answer, nor can it be clearly settled. Much of the ethical dilemma surrounding hESCs relies on individual beliefs about life and the potential for scientific advancement versus creating new human life.