After the ground-breaking news last week that Japanese scientists were able reprogram adult cells to embryonic-like cells in mice by simply bathing them in weak acid, the next step was to try this with human cells. The technique is called “stimulus-triggered acquisition of pluripotency”, or STAP.
With lightening speed, Dr. Charles Vacanti at Harvard Medical School has announced that they have created STAP human cells. New Scientist has the story:
Talk about speedy work. Hot on the heels of the news that simply dipping adult mouse cells in acid could turn them into cells with the potential to turn into any cell in the body, it appears that the same thing may have been done using human cells.
The picture above, given to New Scientist by Charles Vacanti at Harvard Medical School, is said to be images of the first human “STAP cell” experiments….
Now, Vacanti and his colleagues say they have taken human fibroblast cells and tested several environmental stressors on them in an attempt to recreate human STAP cells. He won’t reveal what type of stressors were applied but he says the resulting cells appears similar in form to the mouse STAP cells. His team is in the process of testing to see just how stem-cell-like these cells are.
The Independentalso reports that more tests are needed to see if these stem cells are for real:
“The process was very similar to the one we used on mouse cells, but we used human dermal fibroblasts that we purchased commercially,” Dr Vacanti said. “I can confirm that stem cells were made when we treated these human cells. They do the same thing [as the mouse cells].
“They revert back to stem cells, and we believe the stem cells are not a contamination in the sample that we were inadvertently sent by the company, but that they are being made, although we still have to do the final tests to prove this,” he added.
Clearly this breakthrough has yet to be proven or published in a peer-review journal, but that does not mean that we should not be concerned.
Unlike induced pluripotent stem cell technology (iPSCs) that uses a different method to reprogram adult cells, STAP, in mice, looks like it produces totipotent cells, not just pluripotent cells.
What is the difference? Pluripotent cells cannot become placenta and so could not implant and grow a new organism if placed in a uterus. Totipotent cells can become placenta and so are able to implant and grow into a fetus.
The only other place we find totipotent cells are directly after fertilization. In other words totipotent cells, are very early embryos. New Scientist, in an earlier story, explains why this is such big news:
“The team haven’t just made pluripotent cells like embryonic stem cells,” says José Silva from the University of Cambridge, “they appear to have made totipotent cells.” This means the cells have been rewound to a state with even more flexibility than pluripotent cells, which means they should be easier to manipulate. The only cells known to be totipotent – able to form an embryo and a placenta – in the body are those that have only undergone the first couple of cell divisions immediately after fertilisation. “They are like precursors to embryonic stem cells,” says Silva.
“The word totipotent brings up all kinds of issues,” says Robert Lanza of Advanced Cell Technology in Marlborough, Massachusetts. “If these cells are truly totipotent, and they are reproducible in humans then they can implant in a uterus and have the potential to be turned into a human being. At that point you’re entering into a right-to-life quagmire”
So if STAP produces totipotent cells in humans like it seems to do in mice, then STAP would be a way to clone human beings. And, these would be true clones, not like the ones produced so far with somatic cell nuclear transfer (SCNT) which have DNA from the egg used in the cloning process.
Vacanti admits the possibility of using STAP for cloning to The Independent:
Asked whether it would be possible in theory to follow on from the mouse research to show that skin cells could be turned into viable human embryos – effectively a clone of the donor of the skin samples – Dr Vacanti said: “This is an offshoot, an unintended consequence, so the answer is ‘yes’ …. This would be the natural conclusion, but I won’t be the one that does it.”
I have no doubt that someone will dare to go where Dr. Vacanti says he won’t; especially since the United States has no federal laws against human cloning for research or for reproduction.
Whether or not STAP produces stem cells in human cells still has to be proven and whether those stem cells are pluripotent or totipotent remains to be seen.
What is clear is that, if all it takes to clone a human being is taking a skin cell and placing it in an acid bath, then the world as we know it is about to change drastically.
It may be the only time, but I agree with Robert Lanza:
“The reprogramming step seems to be quite simple, it could be very inexpensive technology for reproductive medicine,” agrees Lanza. “But it has more potential for abuse than iPS cells. It’ll be interesting how this all plays out, but if it’s possible to do this in humans, it changes everything.”