|Stem cells can become any sort of cell in our body.|
hESCs are one type of three different cells, the other two being adult stem cells and induced stem cells. hESCs are produced via "derivation," a process which yields "lines" that replicate indefinitely for use in scientific research. In contrast to hESCs, which can become any cell in the body, adult stem cells are limited to only producing certain types of special cells. The third type is the induced stem cell, where viruses are used to force adult cells into pluripotency. By taking cells from an intended recipient and inserting 3-4 genes into it, scientists can reprogram the cell so that its development is reversed, and it becomes similar to a hESC. Not only can induced stem cells become any cell type in the body like hESCs, they do not trigger an immune response because they are a precise genetic match to their recipient. By coaxing adult stem cells to behave more like embryonic cells and thus restoring pluripotency, the limitation on which tissues can be formed from adult cells is circumvented. Despite this breakthrough, one of the genes inserted in the process of induction is associated with cancer, and there are no methods as of now for targeted recombination. The gene is inserted into the genome (the DNA) at random, which presents risks. Some progress has been made, with one paper using transposons from insects to put in and subsequently remove the carcinogenic gene from the genome.
The National Institute of Health has recognized the promise that stem cells hold for medicine, and "believes that it is important to simultaneously pursue all lines of research."
However, research's progress is hindered by fierce political debate in Washington, with politicians arguing over the fate of these unspecialized, pluripotent cells for the past 60 years. Ever since stem cells were discovered, the debate has been fierce, as there are many issues involved, from the legality of stem cell research, to the tax dollars that it requires, to the ethical issues involved with derivation (which destroys the embryo). Take a look at the Dickey-Wicker amendment, enacted yearly since its introduction in 1996, which states:
(1) the creation of a human embryo or embryos for research purposes; or(2) research in which a human embryo or embryos are destroyed,discarded, or knowingly subjected to risk of injury or death greaterthan that allowed for research on fetuses in utero under 45 CFR46.204(b) and section 498(b) of the Public Health Service Act (42U.S.C. 289g(b)).
This amendment defines an "embryo" as “any organism, not protected as a human subject under 45 CFR 46 as of the date of the enactment of this Act, that is derived by fertilization, parthenogenesis, cloning, or any other means from one or more human gametes or human diploid cells.”
NIH subsequently received a memo from a government attorney, Harriet S. Rabb, stating embryonic stem cells “are not a human embryo” as defined by the Amendment. Ms. Rabb states stem cells “are not even precursors to human organisms,” because stem cells can only develop into different cell types within the human body, while embryos can potentially develop into human organisms.
More than 10 years later, President Obama has issued this memorandum (whitehouse.gov), stating that the government will give more power to the scientists in terms of in what direction research is to take. In Obama's Executive Order No. 13,505, it states that the “[NIH] may support and conduct responsible, scientifically worthy stem cell research, including human embryonic stem cell research, to the extent permitted by law."
"President Obama is committed to supporting responsible stem cell research and today's ruling was another step in the right direction," said his deputy senior adviser Stephanie Cutter.
With all of this in mind, do you support stem cell research? Do you think induced stem cells hold promise, or disagree with that, and believe that they "hold great peril," in the words of President Bush? Make your voice heard and comment below.