Are STAP Stem Cells a Paradigm Changer? Hopes and Fears

Two papers published in Nature on January 30 describe a new and remarkably simple technique for generating pluripotent cells: that is, cells that can, like embryonic stem cells, develop into many different kinds of cells. From the abstract of the first paper, by Haruko Obokata, Charles Vacanti and six colleagues:

Here we report a unique cellular reprogramming phenomenon, called stimulus-triggered acquisition of pluripotency (STAP), which requires neither nuclear transfer nor the introduction of transcription factors. In STAP, strong external stimuli such as a transient low-pH stressor reprogrammed mammalian somatic cells, resulting in the generation of pluripotent cells.

Slightly less formally, Andrew Pollack of The New York Times explained:

A surprising study has found that a simple acid bath might turn cells in the body into stem cells that could one day be used for tissue repair and other medical treatments.

The work was done on mice, but only a week later a photo was released apparently showing human STAP cells. This extension has not been peer reviewed but if confirmed "could be a paradigm changer," according to Robert Lanza. (Vacanti, according to a profile in the Boston Globe, is "not nearly as circumspect as many scientists, who are reluctant to speak about preliminary results or new research for fear of getting scooped or being wrong.")

But wait, there's more. From the abstract of the second Nature paper, by Obokata and ten colleagues, including Vacanti:

Here we report that reprogrammed STAP cells, unlike embryonic stem (ES) cells, can contribute to both embryonic and placental tissues … Taken together, the developmental potential of STAP cells, shown by chimaera formation and in vitro cell conversion, indicates that they represent a unique state of pluripotency.

These reports sent shock waves around the stem cell world. Can it be that iPS cells — so recently the subject of a Nobel Prize — have been outdated already? Are STAP cells in some way part of normal healing processes? (Is this what salamanders do?) Will they upend concepts of regenerative medicine? Or worse …

The authors carefully avoid using the term totipotent, but they do demonstrate that STAP cells (unlike iPS or ES cells) can form placental tissue. Theoretically, then, they could be transferred directly to a surrogate and develop as pure clones. New Scientist went so far as to suggest that:

Stem cell breakthrough could reopen clone wars

Francis Collins, writing on his NIH Director's Blog, cautioned:

This is enormously interesting scientifically, but has also raised concerns that STAPs might provide a ready pathway to animal, or even human, cloning.

That's almost certainly not going to happen soon, but such concerns serve as a reminder that proper regulation to prevent human reproductive cloning is urgently required, now more than ever.

All of the STAP results do need to be confirmed, though they have been a long time coming. Vacanti, who achieved notoriety in 1997 for the "earmouse," first published hints of it ("spore-like cells in adult mammals") in 2001, but had trouble getting support. Indeed, when Vacanti first met Obokata and her Japanese mentor, before suggesting that the isolation procedure might actually be creating these strange cells, he "asked them not to make fun of him" — only to find they already agreed.

Not everyone does. Paul Knoepfler, the UC Davis stem cell researcher and blogger, has been looking carefully at the papers (1, 2), has interviewed Vacanti, and ran an online poll, most of whose respondents are "not sure" though split almost down the middle on the significance of STAP cells. For the moment, he is skeptical:

I believe the odds are it won't work, at least not in a reasonably close fashion to what was reported in these Nature papers. Sure, we might see some people say to the media or even publish papers indicating that they can kinda sorta almost make STAP-like cells with certain stressors sometimes, but my prediction is that it still won't be very convincing.

I really hope I am wrong and if I am you'll read my happy mea culpa right here.

Knoepfler does note that "we'll know if STAP cells are the real deal within as short as two months because quite a few labs are now trying the technique."

That makes sense. Let's make sure the science is right. And begin figuring out how to apply it appropriately.

Previously on Biopolitical Times:

• Cloning-Derived Stem Cells Raise Policy Questions
• Cloning, De-extinction, and Possibly Human Applications
• Induced Pluripotent Stem Cells and Germline Engineering
• A New Technique for Human Genetic Modification?