April 26, 2014

New Stem Cell Research Revives Legal Debates Over Human Cloning

Stem cell scientists report the successful use of somatic cell nuclear transfer (SCNT) to create human embryonic stem cells (hESC) from an adult donor, effectively creating a population of therapeutically available cells to treat disease. This general technique, called therapeutic cloning, affords an opportunity to treat patients with genetically identical stem cells for any number conditions where new cells or replacement cells are needed (e.g., diabetes, Parkinson’s, spinal cord injuries). The investigators were able to generate of embryonic stem cells from a 35-year old and a 75-year old donors. Earlier research had demonstrated the generation of hESC if fetal or infant cells were the donors. Because human embryos were created and used to derive the hESC, the new research revives debates over the potential for advances in therapeutic stem cell research to simultaneously open the door to the misuse of these techniques for reproductive cloning, the generation of a cloned embryo that could be implanted and brought to term (a dual-use characterization). 

This debate is not new – these questions emerged at the first publication and use of somatic cell nuclear transfer (SCNT) to create the cloned sheep, Dolly, in 1997. In that period, with the recognition that advancing technical achievements might result in attempts to try human reproductive cloning, legislative efforts to ban both therapeutic and reproductive cloning or only reproductive cloning emerged at the state and national level in the U.S., as well as internationally. Subsequent research since 1997 revealed that cloning (using somatic cell nuclear transfer, SCNT) was easier to achieve with animals than with humans, until now, which is why this new research puts human cloning back into debate. The flash points in the legal debate are several: whether embryos can be  created for the sole purpose of producing genetically optimal stem cells, whether embryos can be destroyed during the derivation of human embryonic stem cells – and then the dual-use dilemma where the creation of an embryo could be a predicate to stem cell derivation or to reproduction. The Bush administration imposed a ban on federal funding for the derivation of hESC, and only allowed funds to be used on existing cell lines. In 2009, the Obama administration reversed that course and issued guidelines which allowed federal funds to be used to derive new embryonic stem cell lines from already-existing embryos (from fertility clinics). NIH maintains a hESC registry that catalogues cell lines that can be studied with federal funds. In 2011, a legal challenge to the Obama policy emerged from several adult stem cell researchers who alleged that allowing federal funds for hESC research violated the federal Dickey-Wicker amendment, which prohibits the creation of embryos for research or the destruction of embryos during research (see earlier post). In Sherley v. Sebelius (D.C. Cir. 2012), the D.C. Circuit upheld the Obama policy, finding that destruction of embryos that occurs in the ESC derivation process was not a part of individual ESC research projects using already derived ESCs:
Therefore, ESC research is no more “research in which...embryos are...subjected to risk” than it was “research in which...embryos are...destroyed.”  
With the demonstration that hESC can be derived from older human donors, human therapeutic cloning appears more viable and commercially attractive (older patients with degenerative conditions are a prime target). Will this lead to a demand for new cloning-related laws to avoid the dual-use potential? It’s unlikely right now, as the new research is an expansion of already existing technologies, rather than a paradigm-shifting breakthrough. Yet, making human embryo cloning technically possible revives the concerns that animated late-1990s legislative activity. For example, recently introduced legislation, H.R. 2433, distinguishes federal support for embryonic stem cell research from any endorsement of "human cloning:"
Defines "human cloning" to mean the implantation of the product of transferring the nuclear material of a human somatic cell into an egg cell from which the nuclear material has been removed or rendered inert into a uterus or the functional equivalent of a uterus. 
Yet, another bill, H.R. 2164, would prohibit both therapeutic and reproductive cloning with its more expansive definition of human cloning:
(1) Human cloning.--The term `human cloning' means human asexual reproduction, accomplished by introducing the nuclear  material of a human somatic cell into a fertilized or unfertilized oocyte whose nucleus has been removed or inactivated to produce a living organism (at any stage of development) with a human or predominantly human genetic constitution. 
A patchwork of state laws address cloning: several states maintain bans on all human cloning (prohibit conduct per se, or disallow use of state funds), while other states allow therapeutic, but not reproductive cloning (including authorizing use of state funds). The stem cell field is more scientifically complex now than it was in 1998, with techniques using adult stem cells and induced pluripotent stem cells (neither of which are derived from human embryos) also competing for therapeutic supremacy, and avoiding the legal and moral questions attaching to the derivation and use of hESC.

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