Generally speaking, the American public is well accustomed to the concept of tissue and organ transplantation, as stories of life-saving heart and kidney transplants, or American Red Cross blood drives collecting blood and platelets for transfusions have become commonplace. Since these procedures typically require a transfer of tissue from one patient to another, physicians must be careful to choose well-matched donors to avoid rejection by the recipient’s immune system.
But what about other specialized tissues that can be affected by disease, such as those of the eye? A recent study published in the journal Stem Cells by Winston Kao and colleagues describes a method of tissue engineering using stem cells from hair follicles to treat patients suffering from a specific type of corneal disease. The study also provides a fascinating insight into the ways in which adult stem cell research is being used to advance the field of personalized medicine, a growing field which seeks to customize treatments based on the individual patient, especially in terms of genetics.
When stem cells are lost, so is the reservoir for new cells, and this can be a cause of disease in organs such as the human eye. The corneal epithelium, which covers the front of the cornea and protects it from the outside environment, requires limbal stem cells to replenish it, and limbal stem cell deficiency (LSCD) is associated with a loss of vision. If a patient suffers from LSCD in one eye, the most obvious solution is to use tissue from the healthy eye to repair the damage. However, when LSCD occurs in both eyes, an alternate source for stem cells is required.
In Kao’s study, stem cells were isolated from the hair follicles of adult mice, cultured into corneal epithelial cells, and successfully transplanted onto the eyes of mice in which the limbal stem cells had been removed. While this approach has not yet been tried in human patients, there is a great deal of confidence that the treatment will translate effectively. And there are several potential benefits to such treatment. First, it could be used in patients suffering from LSCD in both eyes. Second, the source of the cells would be the same patient, thus minimizing the potential for rejection of the transplanted tissue by the immune system. And third, the cells of the hair follicle share many commonalities with those of the corneal epithelium, including their origins in the developing embryo, which would seem to make them a promising choice for this type of treatment.
A qualification is in order: These findings have great potential to help only one specific group of patients suffering from bilateral LSCD, for whom there has been a lack of effective treatment thus far. Nevertheless, Kao’s report is but one of many detailing the advances being made using adult stem cells, both in isolation techniques and in potential therapeutic use. From a pro-life perspective, it is always good news when medical advances can be made without ethical compromise, and this is why the benefits of adult stem cell research are often cited by those seeking to argue against the use of human embryonic stem cell isolation, which requires the destruction of human embryos.
Yet such advances are not sufficient, either practically or morally, to address the problems with human embryonic stem cell research and potential therapies derived therefrom. Scientific research is done with specific goals in mind, but by design its results are not known until they have been obtained in a replicable manner; and although the contributions to medicine by adult stem cell research may dwarf those obtained in human embryonic stem cells, this fact might reasonably point to a “both-and” rather than an “either-or” attitude toward their use. That is, successes in adult stem cell research do not by themselves necessarily entail the abandonment of embryonic stem cell research, especially since the ephemeral “promise” of embryonic stem cell research is so deeply rooted in the minds of many advocates of the practice.
Solid ethical argument will be centered upon the recognition that some research methods disregard the dignity and integral good of the person while other methods uphold it. It is essential that the basis of our arguments against embryonic stem cell research be made primarily, if not exclusively, on the fact that innocent human life is taken. Evil acts must be rejected regardless of their real or potential efficacy in producing a desired effect. As Blessed John Paul II wrote in Veritatis Splendor, “Only the act in conformity with the good can be a path that leads to life.”
Still, in a culture in which the protection of life is such a contentious issue in healthcare and biomedical research, it is heartening to see examples of treatments emerging in which the life of one does not have to be taken for the treatment of another.
Rebecca Oas is a Fellow of HLI America, an educational initiative of Human Life International. She is also a postdoctoral fellow in the Cell Biology Department at Emory University. Her writings may be found on HLI America’s Truth and Charity Forum.
From hair to cornea: toward the therapeutic use of hair follicle-derived stem cells in the treatment of limbal stem cell deficiency. Meyer-Blazejewska EA, Call MK, Yamanaka O, Liu H, Schlötzer-Schrehardt U, Kruse FE, Kao WW. Stem Cells. 2011 Jan;29(1):57-66
Pope John Paul II, Veritatis Splendor.
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