Argibay González, BárbaraTrekker, JesseHimmelreich, UweBeiras Iglesias, AndrésTopete Camacho, AntonioTaboada Antelo, PabloPérez Mato, MaríaVieites Prado, AlbaIglesias Rey, RamónRivas Rey, JoséPlanas, Anna M.Sobrino Moreiras, TomásCastillo Sánchez, José AntonioCampos Pérez, Francisco2020-06-062020-06-062017Argibay, B., Trekker, J., Himmelreich, U. et al. Intraarterial route increases the risk of cerebral lesions after mesenchymal cell administration in animal model of ischemia. Sci Rep 7, 40758 (2017). https://doi.org/10.1038/srep407582045-2322http://hdl.handle.net/10347/22870Mesenchymal stem cells (MSCs) are a promising clinical therapy for ischemic stroke. However, critical parameters, such as the most effective administration route, remain unclear. Intravenous (i.v.) and intraarterial (i.a.) delivery routes have yielded varied outcomes across studies, potentially due to the unknown MSCs distribution. We investigated whether MSCs reached the brain following i.a. or i.v. administration after transient cerebral ischemia in rats, and evaluated the therapeutic effects of both routes. MSCs were labeled with dextran-coated superparamagnetic nanoparticles for magnetic resonance imaging (MRI) cell tracking, transmission electron microscopy and immunohistological analysis. MSCs were found in the brain following i.a. but not i.v. administration. However, the i.a. route increased the risk of cerebral lesions and did not improve functional recovery. The i.v. delivery is safe but MCS do not reach the brain tissue, implying that treatment benefits observed for this route are not attributable to brain MCS engrafting after stroke.eng© The Author(s) 2017. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/http://creativecommons.org/licenses/by/4.0/journal article10.1038/srep40758open access