It is only a drop in the bucket of the currently available knowledge on neural differentiation, however. According to Human Embryonic Stem Cells: A Practical Handbook, there are seventeen acknowledge and reviewed methodologies for differentiating human embryonic stem cells into neural cells (Walsh, 2008). The incompleteness and erros of this same book, however, reflect the dearth of research into the area of human embryonic stem cell research (Walsh, 2008). Though many advances have been made -- and indeed are being made right now -- the ethical concerns regarding human embryonic stem cells have proven a greater obstacle than the scientific community can fully surmount. This is not to say that ethical considerations are the only reason for a lack of knowledge, either; science, when performed carefully, is usually a slow process, and the benefits and implications of human embryonic stem cell research are far too meaningful and profound to warrant any rushing to hasty conclusions.
It is true that research has provided many insights into specific types of differentiation. The understanding of the differentiation process as a while, however, is still very much in need of further research before a full and accurate description of the processes and mechanisms involved can be achieved. The amount of time that genetic processes themselves have begun to be understood on a physiological and chemical level can only be measured in decades; research into the basic transcription process is not complete. The more complex process of differentiation in human baryonic stem cells is still many years away from a full understanding.
Research presses on, however, and the differentiation of human embryonic stem cells into cardiac and myocardial tissue is another particular area of research that has been receiving much attention lately. The heart is the first organ to be formed in the embryo, and this process occurs within the first few days of conception (Nury et al., 2009). The embryonic stem cells that make up the heart and the constituent vessels must differentiate very early, then, and for this reason they have long fascinated the scientific and medical community (Nury et al., 2009). In a literature and methodology review, David Nury, Tui Neri, and Michel Puceat describe the various methodologies that have been observed and experimentally replicated -- or entirely created through innovative thinking and technologies -- for differentiating human embryonic stem cells in heart tissue and related components (Nury et al., 2009).
The processes that are used in artificial human embryonic stem cell differentiation range from controlling biological factors to the introduction of non-biological and even inorganic compounds to in vitro stem cell cultures in an attempt to manipulate the chemical processes that regulate transcription of the genetic information contained in DNA (Nury et al., 2009). The details are incredibly technical, but what is certain is that for every new discovery made concerning genetic transcription as it relates to human embryonic stem cell differentiation, more questions are raised. This is generally the way of science, especially when direct observation is unavailable. With all genetic studies, very careful measurements of observable phenomenon must be conducted, and causation deduced from the set-up of the experiment and examination of previous data and conclusions, making certainty more difficult (Nury et al., 2009).
Not all research conducted with human embryonic stem cells is done on humans, however, and the replication of certain finding in other animals helps to provide a level of certainty about other findings. In one study, human embryonic stem cells were manipulated and injected into mice in an attempt to reverse hyperglycemia (Mao et al., 2009). The results were hugely successful, and the authors of this study project that the same treatment -- modified, of course, though technically easier to achieve as it would be using same-species stem cells -- will be able to combat diabetes in humans within the next decade, if approval for the therapy is granted (Mao et al., 2009). Again, this underlines the ethical issues with human embryonic stem cell research; even as scientists are gathering evidence as to the potency of stem cell treatments, and even developing treatments that require the use of such methods, they are unsure that their results will be of any practical us in the near or even the distant future (Mao et al., 2009).
Even the present state of research is heavily in question. A review conducted by Lief Fenno, Leon Ptaszek, and Chad Cowan of the past decade of human embryonic stem cell research claims that "stem cell technology, despite its enormous potential, has yet to yield any novel therapies (Fenno et al., 2008). Though this is true insofar as practical human applications are concerned, the authors of this study go on to list some major advancements in stem cell research (Fenno et al., 2008). It is only the practice of new therapies that has yet to fully emerge, and this can largely be ut down to political and religious pressure. Ethical considerations should not be made lightly, but the advance of medicine should not be stopped by unscientific complaints.
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Barthelery, M.; Jaishankar, a.; Salli, U. & Vrana, K. (2009). "Reptin52 expression during in vitro neural differentiation of human embryonic stem cells." Neuroscience letters, 452, pp. 47-51.
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