Abstract
Background aims. Stem cells have been shown to have a therapeutic effect in several ischemic animal models, including hindlimb ischemia and chronic wound. We examined the wound-healing effect of secretory factors released by human embryonic stem cell (hESC)-derived endothelial precursor cells (EPC) in cutaneous excisional wound models. Methods. hESC-EPC were sorted by CD133/KDR, and endothelial characteristics were confirmed by reverse transcription (RT)-polymerase chain reaction (PCR), Matrigel assay and ac-LDL uptake. Conditioned medium (CM) of hESC-EPC was prepared, and concentrated hESC-EPC CM was applied in a mouse excisional wound model. Results. hESC-EPC CM accelerated wound healing and increased the tensile strength of wounds after topical treatment and subcutaneous injection. In addition, hESC-EPC CM treatment caused more rapid re-formation of granulation tissue and re-epithelialization of wounds compared with control vehicle medium and CB-EPC CM-treated wounds. In vitro, hESC-EPC CM significantly improved the proliferation and migration of dermal fibroblasts and epidermal keratinocytes. hESC-EPC CM also increased the extracellular matrix synthesis of fibroblasts. Analysis of hESC-EPC CM with a multiplex cytokine array system indicated that hESC-EPC secreted distinctively different cytokines and chemokines, such as epidermal growth factor (EGF), fibroblast growth factor (bFGF), fractalkine, granulocyte–macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-6, IL-8, platelet-derived growth factor-AA (PDGF-AA) and vascular endothelial growth factor (VEGF), which are well known to be important in normal angiogenesis and wound healing. Conclusions. This study has demonstrated the wound-healing effect of hESC-EPC CM and characterized the spectrum of cytokines released by hESC-EPC that are functionally involved in the wound-healing process. These results suggest that secretory factors released from stem cells could be an important mediator of stem cell therapy in ischemic tissue diseases.
Acknowledgments
This research was supported by a grant from the Korea Healthcare Technology R&D Project, Ministry for Health & Welfare Affairs, Republic of Korea (grant number A085136).
Disclosure of interests: none.