CHARLOTTESVILLE, Va. (BP) -- Stable human embryonic stem cell lines, or hESCs, were first reported and described for scientific research in 1998. To some, these cells promised an ideal source of testing material for new drugs and therapies because they could be grown in the lab indefinitely without losing their characteristics and turn into any cell in the body.
However, the ethical roadblocks for using hESCs -- destroying human embryos is required to isolate the cells -- cannot be overlooked.
Though embryonic stem cells have vocal supporters in the scientific community, most researchers take the ethical problem seriously, and the majority of medical research has advanced without their use. Adult stem cells -- regenerative cells taken from consenting adults -- are used in the vast majority of clinical trials, with only 2 of the 1,750 ongoing trials in December 2012 using embryonic cells.
Despite the success in using adult stem cells, there are limits to their functionality. For example, they do not incorporate themselves into any repaired tissue or create new tissue on their own. Adult stem cells mainly affect an injury or defect by releasing helpful proteins and controlling inflammatory responses but ultimately die or are removed by the immune system within a few weeks.
The journal "Human Molecular Genetics" recently published a review of the advances made using a new type of stem cell called induced pluripotent stem cells, or iPSCs. The author of the paper believes that over the last seven years this new type of cell has transformed not just regenerative medicine but biology as a whole.
Discovered in 2006, iPSCs are just as versatile as embryonic cells, and they are able to create any cell type in the body. This new class of stem cells was created by taking skin cells from an adult and treating them with molecules called transcription factors that alter which genes are active within a cell.
Researchers were able to use these transcription factors to induce the adult cells into an embryonic state, meaning they behave similarly to cells derived from embryos. Not only has this discovery replaced the perceived need for embryonic stem cells, their origin also has opened up several new opportunities for research and medical practice.
Induced pluripotent stem cells taken from patients with genetic diseases can reproduce important features of that disease in the lab setting. This allows researchers to develop disease modeling techniques that can observe disease progression and effectiveness of new drugs, not just in approximate models, but with real human genetic disorders.
Neural cell types are easily created from iPSCs, and a functional model of Huntington's disease is already in use. Therapy with iPSCs also opens up the possibility of using a patient's own cells as part of a treatment that replaces tissue destroyed by disease and injury, reducing the chance of the immune system killing therapeutic cells derived from another source.
New possibilities for reducing age-related disorders also are on the horizon due to the research involving iPSCs. Skin cells from a 100-year-old person have been induced back to a stem cell-like state and behave like cells acquired from young individuals.
Evidently, we can rejuvenate our cells and renew stem cell activity no matter our age. Macular degeneration and retinitis pigmentosa are two age-related disorders that, at least in the lab, can be repaired with iPSC therapies.
Induced pluripotent stem cells have not solved all of the challenges found with embryonic stem cells. There are still the shared problems with tumor formation in some applications and immature development of many cell types. However, these are challenges to current scientific protocols, not ethical challenges.
Predictions of when new therapies will be available are difficult to make, but the possibilities already include disease modeling, simple organ generation and cellular rejuvenation.
These developments should be encouraging to those who have stood against the destruction of human embryos and the use of human embryonic stem cells even when no alternative had yet been found.
The discovery of induced pluripotent stem cells shows that science does benefit from being held to ethical standards.
The ethical roadblocks to using embryonic stem cells guided scientific research into a new direction, meeting the functionality of embryonic stem cells with an ethical alternative and, at the same time, opened up new areas of application.
Joshua Bush, son of the late seminary professor L. Russ Bush, has a Ph.D. in chemical engineering. He is a deacon at First Baptist Church Park Street in Charlottesville, Va. Get Baptist Press headlines and breaking news on Twitter (@BaptistPress
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