Skip to main content
Premium Trial:

Request an Annual Quote

Technical Tidbits

The Riken research team behind the recent pair of papers that purport to show a new method to derive stem cells — a method that has come under fire — has released a tipsheet that they say will help scientists trying to replicate their work, the Nature News Blog reports.

At the end of January, a team led by Haruko Obokata reported in Nature that embryonic-like mouse stem cells could be derived by exposing mouse blood cells to a strong stimulus, such as an acid bath through an approach they dubbed stimulus-triggered acquisition of pluripotency, or STAP.

Questions about the group's studies soon arose because of apparent irregularities regarding images included in the publications — one picture seems to have been used twice — and because other researchers had difficulties reproducing the method. The team said that the image problems stemmed from honest errors. Both Riken and Nature are investigating.

These new technical tips, from Obokata, Hitoshi Niwa, and Yoshiki Sasai at the Riken Center for Developmental Biology, attempt to address the replication issues. "Despite its seeming simplicity, this procedure requires special care in cell handling and culture conditions, as well as in the choice of starting cell population," they write. The sheet is available at the Nature Protocol exchange.

The Riken researchers point out a few tidbits that they say are important. Namely, they note that primary cells should be used, that cells from mice older than a week show low reprogramming levels, and that keeping cell density between about 1x105 and 1x106 cells per square centimeter of culture surface is critical, among other guidelines.

Martin Pera, a stem-cell researcher at the University of Melbourne, tells the Nature News Blog that the more detailed methods will likely help others trying the approach out. But, he adds, "[t]he additional information does not seem to me to reveal any key procedural detail without which it would be impossible to duplicate the work. It appears instead to reinforce and emphasize some aspects of the technique that were disclosed originally."