We were due, I guess. We went through the redefinition of pregnancy (implanted in a uterus”), embryo (after 14 days or implanted in a uterus), cloning (therapeutic cloning, then somatic cell nuclear transplantation, nuclear transplantation, patient specific stem cells, production of “early stem cells, etc.)
And now, we’re supposed to move the line of “embryonic” to eight weeks of gestation.
And we should just forget all the past promises about “14 days,” implantation, along with our objections to killing the youngest of our children.
Some of us have warned that embryonic stem cell research, with it’s high risk of teratomas – tumors that (to paraphrase a popular slogan) “contain all the cell lines in the body,” would lead to further maturation of human embryos into the fetal stage of development. Since the goal is usable tissues and stem cells, it made sense to us that researchers will eventually get around to demanding for funding to grow the embryos in human or surrogate wombs in order to “save lives,” and further their grant requests.
There have been previous examples (I’m on my way to a meeting, so the references will have to wait ’till tonight) in production of “embryonic” nerve tissues being used to treat a few children with neurological metabolic diseases. In fact, the “embryonic” tissues used to harvest these cells must come from children who are aborted at 7 to 9 weeks, technically fetuses, not embryos.
Further evidence of the possible direction of stem cell research – if we allow it – comes to us this week, from the online journal, PLOS-Medicine.
Here’s the press release that showed up in my Google alerts file, from Eureka News Alerts, “Human stem cell transplants mature into neurons and make contacts in rat spinal cord.”:
Human stem cell transplants mature into neurons and make contacts in rat spinal cord
Human nerve stem cells transplanted into rats’ damaged spinal cords have survived, grown and in some cases connected with the rats’ own spinal cord cells in a Johns Hopkins laboratory, overturning the long-held notion that spinal cords won’t allow nerve repair.
A report on the experiments will be published online this week at PLoS Medicine and “establishes a new doctrine for regenerative neuroscience,” says Vassilis Koliatsos, M.D., associate professor of neuropathology at Johns Hopkins. “The spinal cord, a part of the nervous system that is thought of as incapable of repairing itself, can support the development of transplanted cells,” he added.
“We don’t yet know whether the connections we’ve seen can transmit nerve signals to the degree that a rat could be made to walk again,” says Koliatsos, “We’re still in the proof of concept stage, but we’re making progress and we’re encouraged.”
In their experiments, the scientists gave anesthetized rats a range of spinal cord injuries to lesion or kill motor neurons or performed sham surgeries. They varied experimental conditions to see if the presence or absence of spinal cord lesions had an effect on the survival and maturation of human stem cell grafts. Two weeks after lesion or sham surgery, they injected human neural stem cells into the left side of each rat’s spinal cord.
After six months, the team found more than three times the number of human cells than they injected in the damaged cords, meaning the transplanted cells not only survived but divided at least twice to form more cells. Moreover, says Koliatsos, the cells not only grew in the area around the original injection, but also migrated over a much larger spinal cord territory.
Three months after injection, the researchers found evidence that some of the transplanted cells developed into support cells rather than nerve cells, while the majority became mature nerve cells. High-powered microscopic examination showed that these nerve cells appear to have made contacts with the rat’s own spinal cord cells.
The research was funded by the National Institute of Neurological Disorders and Stroke, the Muscular Dystrophy Association and the Robert Packard Center for ALS Research at Johns Hopkins.
Authors on the paper are Jun Yan, Leyan Xu, Annie M. Welsh, Glen Hatfield and Koliatsos, all of Hopkins, and Thomas Hazel and Karl Johe of Neuralstem of Rockville, Md.
On the Web:<a href=”
There is nothing alarming – and quite a bit that’s encouraging – in that press release. However, reading the actual published articles leads to the discovery that the stem cells in question come from human fetuses. I’m afraid that I don’t know of any way to harvest neural stem cells from human fetuses without harming those unborn children.
Here’s the first article, “Extensive Neuronal Differentiation of Human Neural Stem Cell Grafts in Adult Rat Spinal Cord.”
And the second, which explains where we are going:”Making Human Neurons from Stem Cells after Spinal Cord Injury”
Spinal cord cells were obtained from cervical and upper thoracic spinal cord of an eight-week-old human embryo and expanded in monolayer culture in defined medium with the mitogen FGF2 (a member of the fibroblast growth factor family).
In the future, perhaps fetal neural stem cells can be developed from cells harvested from placentas collected after the birth of children or as a by-product of amniotic fluid tests done for medical indications and then used as we use other cellular and tissue transplants of adult stem cells and specialized tissues.
Perhaps Dr. Atala and his research group could follow this line.
However, I expect to see a call for more money for fetal stem cell research and for a demand for an expansion of the time that human “extracorporeal” embryos can be maintained.
And won’t it be interesting to see how these nascent human beings are grown to eight weeks or so?