Allogeneic Mesenchymal Stem Cells for the Survivors of Ischemic Stroke Trial (ASSIST)

Inclusion Criteria: * 18 years or older. * Clinical diagnosis of ischemic stroke for more than 6 months. * Imaging findings suggestive of ischemic stroke with functional deficits at initial diagnosis and enrollment. * Severe neurological impairment associated with the diagnosis of ischemic stroke that resulted in the subject needing assistance to walk or not being able to perform general daily activities independently. * No substantial improvement in neurologic or functional deficits for the 2 months prior to enrollment. * NIHSS score between 6-20. * Life expectancy longer than 12 months. * Prior to treatment, the patient received standard medical care for secondary prevention of ischemic stroke, including but not limited to appropriate blood pressure and cholesterol control measures, use of antiplatelet agents or anticoagulants (except when prohibited). * Understand and provide signed informed consent, or have a designated legal guardian or spouse make such decision voluntarily on behalf of the subject. * Expected that the patient will receive standard medical care for secondary prevention of ischemic stroke and participate in all planned safe follow-up visits reasonably. * Organ function as defined by the following criteria: AST ≤ 2.5×ULN ALT ≤ 2.5×ULN TSB ≤1.5×ULN PT ≤1.25×ULN and PTT ≤1.25×ULN in subjects who did not receive antithrombotic therapy Serum albumin ≥ 3.0g/dL ANC ≥ 1,500/μL Platelets ≥ 150,000/μL Hemoglobin ≥ 9.0g/dL Serum creatinine ≤ 1.5×ULN Serum amylase or lipase ≤ 1.0×ULN Exclusion Criteria: * History of epilepsy. * History of cancer. * History of brain trauma and brain tumor. * Positive for hepatitis B surface antigen, E antigen, E antibody, core antibody, hepatitis C, HIV or RPR. * Myocardial infarction occurred within six months of study entry. * Any other medical problems of clinical significance, abnormal mental or test results that the investigator or sponsor determined participating in the study pose a safety risk to the subject. * Imaging findings suggestive of subarachnoid hemorrhage or intracerebral hemorrhage in the past 12 months. * Participation in any study of experimental drug or device within 3 months. * Participation in other study related to stem cell-therapy. * History of drug or alcohol abuse within 1 year. * Pregnant, lactating or planning to become pregnant during the trial. * Allergic to cattle or pork products.