Evaluate the Safety and Explore Efficacy of Umbilical Cord Mesenchymal Stem Cells in Acute Ischemic Stroke

There will be one dose of IV administration in patients with acute ischemic stroke, or one dose of IV administration followed by low or high doses of IA infusion for acute ischemic stroke with or without bridging therapy (i.e. Intravenous rt-PA thrombolysis or intraarterial thrombectomy) with 12 months of follow up after the first treatment.