G-CSF–mobilized bone marrow cells do not incorporate into the regenerating liver vasculature. (A) Experimental outline of PHx-induced liver regeneration in C57BL/6N mice. Prior to the angiogenic phase (on day 2 after PHx), mice were injected subcutaneously with 100 µg G-CSF (as a regenerative therapy) to mobilize bone marrow–derived progenitor cells. (B) The frequency of circulating LSK cells in the peripheral blood of sham-operated and PHx mice was analyzed by FACS (mean ± SD, n = 5 mice). (C) The ratio of CD133⁺ ECs in the livers of sham-operated and PHx mice was analyzed by FACS (mean ± SD, n = 5 mice). (B and C) Saline-injected mice served as controls. (D) Representative images of liver sections of sham-operated and PHx mice costained with CD133 (progenitor cell marker), CD45, and liver EC–specific marker (Lyve-1/Col-IV). Zoomed-in images are shown at the bottom. Arrows indicate CD133⁺ cells. All traced CD133⁺ cells were negative for CD45 and EC markers. Scale bars, 50 µm. Two-tailed Student’s t test.