Figure 2. Recreation of the human endometrium and its components from ESP cells in immunodeficient mice.

(A) The macroscopic appearance of an ESP-initiated lesion (surrounded by white arrowheads) in the kidney of a NOD/SCID/γ_c ^null (NOG) mouse treated with E₂ pellets for 10 weeks. Bar, 1 mm. (B) H&E-stained section of the same lesion indicated in (A). A small box marks a region shown at a higher magnification in the adjacent panel as indicated. Bars, 500 µm (left) and 100 µm (right). (C) H&E-stained and immunofluorescence images of ESP- or EMP-initiated lesions co-stained with DAPI and antibodies against CK and Vm where various endometrial cell components were formed. The right table shows the number and frequency of the ESP- or EMP- initiated mice which predominantly possessed human endometrium with glandular structures, vessel-like structures consisting of endothelial cells, migrating endothelial cells, or stromal cell components. Bars, 500 µm. (D) Immunofluorescence images of serial sections of the ESP-initiated lesion co-stained with DAPI and antibodies against αSMA and hCD31. Note that ESP-initiated vessel-like structures positive for hCD31 and Vm were surrounded by muscle-like layers positive for αSMA and Vm. Bars, 100 µm. (E) Immunofluorescence images of the same lesion as (A) co-stained with DAPI and antibodies against CK and vimentin (Vm). Bars, 500 µm. The borders between the reconstituted tissue and the mouse kidney (MK) are indicated by the dotted lines. (F) Immunofluorescence images of the ESP-initiated lesion co-stained with DAPI and antibodies against human CD31 (hCD31) and Vm in NOG mice. Yellow arrowheads indicate hCD31-positive cells. Bars, 200 µm. (G) Immunofluorescence images of the ESP-initiated lesion co-stained with DAPI and antibodies against PR and Vm. Bars, 50 µm.