We evaluated the healing potential of human fetal aorta-derived CD133 ⁺ progenitor cells and their conditioned medium (CD133 ⁺ CCM) in a new model of ischemic diabetic ulcer. Streptozotocin-induced diabetic mice underwent bilateral limb ischemia and wounding. One wound was covered with collagen containing 2×10 ⁴ CD133 ⁺ or CD133 ⁻ cells or vehicle. The contralateral wound, covered with only collagen, served as control. Fetal CD133 ⁺ cells expressed high levels of wingless ( Wnt ) genes, which were downregulated following differentiation into CD133 ⁻ cells along with upregulation of Wnt antagonists secreted frizzled-related protein (sFRP)-1, -3, and -4. CD133 ⁺ cells accelerated wound closure as compared with CD133 ⁻ or vehicle and promoted angiogenesis through stimulation of endothelial cell proliferation, migration, and survival by paracrine effects. CD133 ⁺ cells secreted high levels of vascular endothelial growth factor (VEGF)-A and interleukin (IL)-8. Consistently, CD133 ⁺ CCM accelerated wound closure and reparative angiogenesis, with this action abrogated by coadministering the Wnt antagonist sFRP-1 or neutralizing antibodies against VEGF-A or IL-8. In vitro, these effects were recapitulated following exposure of high-glucose-primed human umbilical vein endothelial cells to CD133 ⁺ CCM, resulting in stimulation of migration, angiogenesis-like network formation and induction of Wnt expression. The promigratory and proangiogenic effect of CD133 ⁺ CCM was blunted by sFRP-1, as well as antibodies against VEGF-A or IL-8. CD133 ⁺ cells stimulate wound healing by paracrine mechanisms that activate Wnt signaling pathway in recipients. These preclinical findings open new perspectives for the cure of diabetic ulcers.

Malignant glial tumors, including glioblastoma multiforme, account for 15 - 20% of pediatric CNS malignancies. They are most resistant to therapy and are associated with a poor prognosis. Given the ability of mesenchymal stem cells (MSCs) to affect glioma growth, we investigated the effects of extracellular vesicles (EVs) derived from MSCs on U87MG glioblastoma cells line. EVs were isolated from culture media of MSCs from different sources, including bone marrow (BM), umbilical cord (UC) and adipose tissue (AT) and added to U87MG culture. The internalization and the effects of BM-, UC- and AT-MSC-EVs on proliferation and apoptosis of tumor cells were evaluated. Both confocal microscopy and FACS analysis showed internalization of EVs into tumor cells. BM- and UC-MSC-EVs decreased cell proliferation, while an opposite effect was observed with AT-MSC-EVs. Moreover, both BM- and UC-MSC-EVs induced apoptosis of glioblastoma cells, while AT-MSC-EVs had no effect. Loading UC-MSC-EVs with Vincristine further increased cytotoxicity when compared both to the free drug and to untreated EVs. Different effects of MSC-EVs on cancer cells were observed depending on their tissue of origin. Moreover, MSC-EVs can deliver antiblastic drugs to glioblastoma cells.