A comparison of the pro-angiogenic potential of human induced pluripotent stem cell derived endothelial cells and induced endothelial cells in a murine model of peripheral arterial disease

Abstract

Background: Endothelial cells derived from human induced pluripotent stem cells (iPSC-ECs) promote angiogenesis, and more recently induced endothelial cells (iECs) have been generated via fibroblast trans-differentiation. These cell types have potential as treatments for peripheral arterial disease (PAD). However, it is unknown whether different reprogramming methods produce cells that are equivalent in terms of their pro-angiogenic capabilities.

Objectives: We aimed to directly compare iPSC-ECs and iECs in an animal model of PAD, in order to identify which cell type, if any, displays superior therapeutic potential.

Methods: IPSC-ECs and iECs were generated from human fibroblasts, and transduced with a reporter construct encoding GFP and firefly luciferase for bioluminescence imaging (BLI). Endothelial phenotype was confirmed using in vitro assays. NOD-SCID mice underwent hindlimb ischaemia surgery and received an intramuscular injection of either 1×10⁶ iPSC-ECs, 1×10⁶ iECs or control vehicle only. Perfusion recovery was measured by laser Doppler. Hindlimb muscle samples were taken for histological analyses.

Results: Perfusion recovery was enhanced in iPSC-EC treated mice on day 14 (Control vs. iPSC-EC; 0.35±0.04 vs. 0.54±0.08, p<0.05) and in iEC treated mice on days 7 (Control vs. iEC; 0.23±0.02 vs. 0.44±0.06, p<0.05), 10 (0.31±0.04 vs. 0.64±0.07, p<0.001) and 14 (0.35±0.04 vs. 0.68±0.07, p<0.001) post-treatment. IEC-treated mice also had greater capillary density in the ischaemic gastrocnemius muscle (Control vs. iEC; 125±10 vs. 179±11 capillaries/image; p<0.05). BLI detected iPSC-EC and iEC presence in vivo for two weeks post-treatment.

Conclusions: IPSC-ECs and iECs exhibit similar, but not identical, endothelial functionality and both cell types enhance perfusion recovery after hindlimb ischaemia.

Keywords: Angiogenesis; Cell therapy; Differentiation; Endothelial cells; Peripheral arterial disease; Reprogramming.