The primary cultured ESCs we used were confirmed immunocytochemically to be positive for vimentin, a marker for stromal cells, and negative for cytokeratin, a marker for epithelial cells (please see above figure). ESCs at early passages (between 2 and 6 passages) were used for the experiment. In this study, the passaged cells were used without freezing. However, we have confirmed that primary ESCs can be cryopreserved in CELLBANKER, and retain characteristics such as responsiveness to decidual stimuli. These descriptions have been added to the revised manuscript (page 3, lines 96-99). Figure. Immunocytochemistry (ICC) of vimentin and cytokeratin in isolated human ESCs.
In primary endometrial stem cell (ESC) culture they demonstrate that chemical induction (by db-cAMP/P4) of pseudo-decidualization in culture is accompanied by decreased PGRMC1 protein levels (fig.2).