Mesenchymoangioblast-derived mesenchymal stromal cells inhibit cell damage, tissue damage and improve peripheral blood flow following hindlimb ischemic injury in mice

Background aims. Existing treatments have limited success in modifying the course of peripheral artery disease, which may eventually lead to limb-threatening ulcers and amputation. Cellular therapies have the potential to provide a new treatment option for this condition, but isolation of cells by conventional means has limitations with respect to reproducibility and scalability. Methods. Induced pluripotent stem cells (iPSCs) were differentiated into precursor cells known as mesenchymoangioblasts (MCAs) and subsequently into mesenchymal stromal cells (MSCs). Hindlimb ischemia in mice was created by ligating both the iliac and femoral arteries of one hindlimb. Immediately after surgery, each animal received intramuscular injections of 5 x 10(6) cells or media in the ischemic limb. Toe necrosis was assessed visually, and hindlimb blood flow was measured by laser Doppler using a set region of interest (ROI) and by tracing the entire foot. Myofiber heterogeneity, nuclear centralization, fatty degeneration, fibrosis and capillary angiogenesis in the gastrocnemius muscle were assessed histologically. Results. Blood flow in the MCA-derived MSC-treated animals was higher at each day (P < 0.006), and these mice recovered faster than control animals (3.6 vs. 2.5 for set ROI; 7.5 vs. 4:1 foot tracing; slope; P < 0.001). There was significantly less myofiber heterogeneity, nuclear centralization, fatty degeneration and fibrosis in MCA-derived MSC-treated animals, indicating less tissue damage. Discussion. MCA-derived MSCs improved limb blood flow, reduced necrosis and maintained muscle mass and gross muscle appearance. We conclude that MCA-derived MSCs have a significant and protective effect against ischemic insults.