Flow and Regenerates Skeletal Muscle in Ischemic Limbs

Objective: Bone marrow cell therapy promotes angio-genesis, but the cellular fate of bone marrow cells (BMCs) in the absence of immunosuppressant inter-ventions is unclear. We created a model of severe hind limb ischemia to address whether BMCs form new blood vessels or differentiate into other tissues. Methods and Results: After ligating the common femoral artery in ApoE knockout mice, we injected either phosphate buffered saline (PBS) or 5 107 adult unfractionated BMCs obtained from green fluorescent protein-positive mice. Laser Doppler imaging of the ischemic limbs revealed that intra-arterial BMCs sig-nificantly increased blood flow recovery in ischemic limbs beginning 21 days after surgery and peaking at 27 days (61.8 % + 15 % vs. 41.9 % + 13.9%, respec-tively, for BMCs and PBS, P <.05). The BMCs differ-entiated into small blood vessels, skeletal myofibers, and supporting membranes, and these changes were associated with increased serum levels of vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF-2), transforming growth factor b (TGF-b), interleukin 4 (IL-4), and tumor necrosis factor a (TNF-a). Conclusions: Adult BMCs injected into ischemic limbs without immunosuppressant therapy differentiated into blood vessels and skeletal myofibers, and this was associated with accelerated blood flow restoration and increased serum levels of VEGF, FGF-2, TGF-b, IL-4, and TNF-a. Skeletal muscle formation may provide benefits beyond angiogenesis to patients with chronic peripheral arterial disease or to patients with low cardiac output states who also suffer from skeletal muscle atrophy