A Subset of Paracrine Factors as Efficient Biomarkers for Predicting Vascular Regenerative Efficacy of Mesenchymal Stromal/Stem Cells

Mesenchymal stromal/stem cells (MSCs) have been developed as a promising source for cell‐based therapies of ischemic disease. However, there are some hurdles in their clinical application such as poor cell engraftment and inconsistent stem cell potency. In this study, we sought to find biomarkers for predicting potency of MSCs for proangiogenic therapy to improve their beneficial effects. Large variations were observed in proangiogenic factor secretion profiles of conditioned media derived from nine different donor‐derived Wharton's jelly (WJ)‐derived MSCs and 8 factors among 55 angiogenesis‐related factors were secreted at considerable levels. Two distinct WJ‐MSCs that had the lowest or the highest secretion of these eight factors showed corresponding proangiogenic activities in in vitro angiogenesis assays. When four additional different donor‐derived WJ‐MSCs were further examined, proangiogenic activities in migration and tube formation of endothelial cells and in in vivo Matrigel plug assay were highly consistent with secretion levels of four major factors (angiogenin, interleukin‐8, monocyte chemoattractant protein‐1, and vascular endothelial growth factor). Such correlation was also observed in vascular regenerative effect in a mouse hind limb ischemia model. Blocking of these four factors by neutralizing antibodies or knockdown of them by siRNA treatment resulted in significant inhibition of proangiogenic activities of not only WJ‐MSCs, but also bone marrow‐derived MSCs. These results suggest that these four factors may represent efficient biomarkers for predicting vascular regenerative efficacy of MSCs. Stem Cells 2019;37:77–88 Heterogeneity in the secretome profiles of mesenchymal stromal/stem cells (MSCs) derived from different donors or tissues results in inconsistent stem cell potency. A minimal set of proangiogenic factors consisting of angiogenin, IL‐8, MCP‐1, and vascular endothelial growth factor that are selected from this study is proposed as efficient biomarkers for predicting vascular regenerative efficacy in the treatment of ischemic disease. These biomarkers will be helpful for manufacturing stem cells that are reproducibly effective in the clinic.