OSAKA -- Scientists at Riken, the Japanese institute behind claims of an ingeniously novel method of creating stem cells, have been unable to duplicate the process despite multiple attempts, sources said Tuesday.
The struggle to verify the results of research published by Haruko Obokata and colleagues earlier this year casts further doubt on the existence of stimulus-triggered acquisition of pluripotency, or STAP, the phenomenon they described. Exposing ordinary body cells to various stresses had made them pluripotent, or able to differentiate into any type of tissue, the authors had claimed.
Riken is expected to release an interim report on the follow-up study in a news conference Wednesday.
Supposed to last a year, the effort began in April at the Riken Center for Developmental Biology in Kobe, the home of the original STAP cell research. As Riken had initially planned it, if STAP were indeed possible, the new experiments would have yielded cells bearing the telltale signs by the end of June. Next would have come implanting these cells in mouse embryos to test whether they really were pluripotent.
But the experiments have been fraught with difficulty from the outset. Bathing mouse cells in a mildly acidic solution, one of the stimuli that Obokata supposedly used to create STAP cells, has produced only faint genetic markers associated with pluripotency, according to sources familiar with the experiments. By this measure, the stressed cells come nowhere near naturally occurring embryonic stem cells or induced pluripotent stem cells created through genetic reprogramming, the sources say.
Obokata has been taking part in the effort to reproduce her own results since July. Riken will consider data from her latest experiments in concluding whether STAP truly exists, which at this point looks highly doubtful, according to the sources.
Tarred by accusations of academic dishonesty, Riken will announce a shake-up of the developmental biology center in Wednesday's news conference. Director Masatoshi Takeichi and several other leading officials are expected to be replaced. The center is also expected to be renamed and have its staff of around 400 researchers cut by half.
Riken will also launch a full investigation into the STAP cell controversy, including allegations that the results were doctored with embryonic stem cells.