Transplantation of BM-derived ALDH^hi cells improved perfusion and capillary density in ischemic limbs. (A-D) Representative LDPI after right femoral artery ligation and tail vein injection of PBS (n = 8), 50 × 10⁶ BM MNCs (n = 6), 5 × 10⁵ ALDH^lo (n = 8), or 1 to 2 × 10⁵ ALDH^hi cells (n = 8) monitored weekly for 21 days. Numbers in the lower left of each LDPI image indicate PR of the ischemic versus the nonischemic limb. (E) Summary of PRs for all mice transplanted as indicated in panels A through D. Transplantation of BM ALDH^hi cells augmented perfusion in ischemic limbs from 7 to 21 days after transplantation (*P < .05). (F) Capillary density at days 21 to 28 was increased in mice transplanted with ALDH^hi cells (*P < .05). All micrographs were viewed with an Olympus (Hamburg, Germany) BX50 microcoscope using air lenses and betaglucuronidase and hematoxylin stains. All images were taken with a Hitachi HV-F2S CCD camera using Northern Eclipse version 7.0 software. The following numeric aperture (NA) air objectives were used: panels C and F, 10×/0.30; panels E and G, 20×/0.50.