Adult Stem Cells Continue to Offer Hope
Advances with adult stem cells continue to promise new cures without violating ethical concerns over embryo research.
Bone from skin: A test of using iPSCs from skin cells to manufacture bone has been successful in rhesus monkeys, Science Daily reports. Also encouraging is that the risk of developing tumors called teratomas appears less than previously thought from experiments on mice. Bone progenitor cells were generated from skin cells derived from the same individual. “Those progenitor cells were then seeded onto ceramic scaffolds that are already in use by reconstructive surgeons attempting to fill in or rebuild bone,” the article explains. “And, it worked; the monkeys grew new bone.
Blood from umbilical cord: Scientists at Mt. Sinai Medical Center have overcome a limitation with cord blood stem cells: small numbers. They identified a technique that causes these cells to “generate in greater numbers making them more useful in adult transplantation,” Science Daily says. With this advance, adults may share in the life-saving treatment used commonly for pediatric patients. With their ability to regenerate blood, these stem cells could be useful to treat leukemia, lymphoma, and other blood-related disorders.”
Poised for greatness: Dr. Bradley Cairns and a team at the University of Utah Huntsman Cancer Institute are finding that sperm progenitor cells are “poised for greatness.” He means that these “mundane” cells that await signals to mature into sperm could be trained to become totipotent (fully capable of differentiation into any cell type); after all, that’s what happens after fertilization with an egg. By learning the methylation signals on the cells that switch on totipotency, the researchers see new avenues for understanding fertilization, cancer and applications for cells that have the “incredible flexibility to mature into skin, heart, gut, or any type of cell.”
Nuclear transfer good in new context : The phrase “somatic cell nuclear transfer” used to wave red flags about the tainted practice of putting nuclei from embryonic cells into body cells (somatic cells), thereby initiating a process of human cloning. But what if the nuclei come from skin cells that have been reprogrammed into “embryonic-like” induced pluripotent stem cells (iPSC)? That capability was demonstrated at Hebrew University of Jerusalem recently. The press release calls this a “Major step toward future therapies for combating life-threatening diseases by cell replacement.”
Are embryonic stem cells needed any more? If nuclear transfer can be achieved with iPSCs, why use embryos? That’s a question Gretchen Vogel hinted at in Science Magazine when reporting about parallel research:
Last week [prior to May 2, 2014] stem cell researchers finally reached a goal that has eluded them through more than a decade of setbacks and scandal. Two teams have independently derived human embryonic stem cells by cloning adult skin cells. The promise of the technique remains tantalizing: replacement tissues for treating diseases from diabetes to Parkinson’s, matched to the patient whose cells gave rise to them. But the practical, ethical, and legal hurdles are as high as ever. The method will also have to prove its worth against a strong competitor: a way to make personalized stem cells that doesn’t involve embryos.
Vogel refers to historical episodes: Dolly the sheep, the Hwang scandal (1/22/14), the Mitalipov announcement (6/20/13), and more. The ethical line she draws seems arbitrary: “Researchers eagerly set out to clone human cells—not to replicate humans, which most scientists strongly oppose, but to generate early human embryos from which stem cells could be harvested.” This is arbitrary in the sense that it’s only a matter of what point on the timeline to stop progression of embryo to adult. Ethical concerns also arise in the treatment of women:
But spurred by ethical worries about undue pressure on women, many organizations and governments prohibit paying egg donors. That includes the California Institute for Regenerative Medicine, a major funder of stem cell research, which put these cells off-limits for its many grantees.
With ethical concerns driving funding laws, why are some labs so willing to continue work on human embryos for somatic cell nuclear transfer (SCNT), otherwise known as “therapeutic cloning”?
Legal issues still constrain SCNT. Many governments forbid or otherwise restrict its use with human cells. In the United States, no federal funding can be used for research that harms or destroys a human embryo, so scientists must set up separate lab space that does not use any National Institutes of Health or other federal grant money. Several U.S. states have banned all human SCNT research.
Vogel seems at a loss to justify continued research with SCNT. Indeed, “The political energy needed to overturn those laws might be hard to generate given that there’s now an embryo-free alternative to producing patient-specific stem cells.” All she can point to is possible flaws in the use of iPSCs. Those flaws seem to be rapidly disappearing with each new advance like those reported above. But until all the differences between embryonic and somatic sources are understood, some scientists want to continue their questionable work.
Imagine if Vogel had said, “The political energy needed to overturn anti-slavery laws might be hard to generate now that there’s a free-market alternative to getting work done.” Good grief; if something is unethical, you don’t do it whether or not there is a benefit. Embryos are not the slaves of the living. If human life is sacred, you don’t treat it like a commodity (see 5/15/14).