Extraordinary stem cell method tested in human tissue

(Image: Charles Vacanti and Koji Kojima, Harvard Medical School)

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.

Last week, the scientific world was bowled over by a study in Nature showing that an acidic environment turned adult mouse cells into "totipotent" stem cells which can turn into any cell in the body or placenta. The researchers called these new totipotent cells stimulus-triggered acquisition of pluripotency (STAP) cells.

"If they can do this in human cells, it changes everything," Rob Lanza of Advanced Cell Technologies in Marlborough, Massachusetts, said at the time. The technique promises cheaper, quicker and potentially more flexible cells for regenerative medicine, cancer therapy and cloning.

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.

Vacanti says that the human cells took about a week to resemble STAP cells, and formed spherical clusters just like their mouse counterparts. Using a similar experimental set-up with green monkey (Chlorocebus sabaeus) cells, Vacanti says the resulting cells are behaving slightly differently. He says that may be due to the fact that the researchers used slightly different techniques. Both Vacanti and his Harvard colleague Koji Kojima emphasise that these results are only preliminary and much further analysis and validation is required.

"Even if these are STAP cells they may not necessarily have the same potential as mouse ones they may not have the totipotency which is one of the most interesting features of the mouse cells," says Sally Cowley, head of the James Martin Stem Cell Facility at the University of Oxford.

Pluripotent cells, such as embryonic stem cells, can form any cell in an embryo but not a placenta. Totipotent cells, however, can form any cell in an embryo and a placenta meaning they have the potential to create life. The only cells known to be naturally totipotent are in embryos that have only undergone the first couple of cell divisions immediately after fertilisation.

Research using totipotent cells would have to be under very strict regulatory surveillance, says Cowley. "It would actually be ideal if the human cells could be pluripotent and not totipotent it would make everyone's life a lot easier."

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Extraordinary stem cell method tested in human tissue