Vascular endothelial growth factor-C derived from CD11b+ cells induces therapeutic improvements in a murine model of hind limb ischemia.

OBJECTIVE: The use of bone marrow cells (BMCs) in therapeutic angiogenesis has been studied extensively. However, the critical paracrine effects of this treatment are still unclear. Therefore, we studied autotransfusable cells that produce vascular endothelial growth factor (VEGF), especially VEGF-C.

METHODS: Male C57BL/6 mice with hind limb ischemia were administered intramuscular injections of phosphate-buffered saline as controls, or unsorted BMCs, sorted CD11b(+), or CD11b(-) cells from BMCs, and recombinant VEGF-C. To evaluate the treatments, perfusion was measured by laser Doppler scanning performed on days 0, 1, 3, 7, 14, 21, and 28. A functional assay was performed in parallel, with mice traversing an enclosed walkway. Capillary density was determined by directly counting vessels stained positive with von Willebrand factor at individual time points. Lymphangiogenesis was assessed by LYVE-1 positive cells.

RESULTS: Postischemic recovery of hind limb perfusion significantly improved in BMC, CD11b(+), and VEGF-C treatment groups compared with the control groups, as assessed by laser Doppler scanning. On early operative days 1 and 3, the blood flow recovery ratio was higher in the CD11b(+)-treated group compared with BMC and VEGF-C treatment groups. In the functional assay, the VEGF-C group dramatically recovered compared with the control group. The capillary/myofiber ratio in the thigh muscle and number of LYVE-1 positive cells was higher in the CD11b(+) and VEGF-C groups than in controls. Furthermore, expression of VEGF-A, VEGF-C, and VEGF receptor messenger ribonucleic acid and protein was observed in CD11b(+) cells.

CONCLUSIONS: The VEGF-C derived from CD11b(+) cells play a critical role in angiogenesis and lymphangiogenesis in a murine model of hind limb ischemia. Consequently, treatment with self-CD11b(+) cells accelerated recovery from ischemia and may be a promising therapeutic strategy for peripheral arterial disease patients.