Delayed Administration of Human Umbilical Tissue-Derived Cells Improved Neurological Functional Recovery in a Rodent Model of Focal Ischemia

Background and Purpose—The short time window required by neuroprotective strategies for successful treatment of patients with ischemic stroke precludes treatment for most. However, clinical therapies based on neuroregeneration might extend this therapeutic time window and thus address a significant unmet need. Human umbilical tissue-derived cells have shown great potential as neuroregenerative candidates for stroke treatment. Methods—The effectiveness of intravenous administration of human umbilical tissue-derived cells was tested in a rodent middle cerebral artery stroke model in a dose escalation study (doses tested: 3105, 1106, 3x106, or 1107 cells/injection) followed by a time-of-administration study (time after stroke: Day 1, Day 7, Day 30, and Day 90 at a dose of 5106 cells/injection). Controls were phosphate-buffered saline injections and human bone marrow-derived mesenchymal stromal cell injections. Post-treatment outcome tools included the modified neurological severity score and the adhesive removal tests. Histology was performed on all cases to evaluate synaptogenesis, neurogenesis, angiogenesis, and cell apoptosis. Results—Statistically significant improvements of human umbilical tissue-derived cell treatment versus phosphate-buffered saline in modified neurological severity scores and adhesive test results were observed for doses 3106 cells up to 30 days poststroke. At doses 3106, histological evaluations confirmed enhanced synaptogenesis, vessel density, and reduced apoptosis in the ischemic boundary zone and increased proliferation of progenitor cells in th