The race is on: human embryonic stem cell research goes global.

More nations are joining the human embryonic stem cell (hESC) "race" by aggressively publishing in the peer-reviewed journals. Here we present data on the international use and distribution of hESC using a dataset taken from the primary research literature. We extracted these papers from a comprehensive dataset of articles using hESC and human induced pluripotent stem cells (hiPSC). We find that the rate of publication by US-based authors is slowing in comparison to international labs, and then declines over the final year of the period 2008-2010. Non-US authors published more frequently and at a significantly higher rate, significantly increasing the number of their papers. In addition, international labs use a more diverse set of hESC lines and Obama-era additions are used more in non-US locations. Even considering the flood of new lines in the US and abroad, we see that researchers continue to rely on a few lines derived before the turn of the century. These data suggest "embargo" effects from restrictive policies on the US stem cell field. Over time, non-US labs have freely used lines on the US registries, while federally funded US scientists have been limited to using those lines approved by the NIH.