Inclusion Criteria:

1. acute ischemic stroke in the MCA circulation, Multimodal MRI inclusion criteria will be:

   • hemispheric strokes > 2.5 cm maximum diameter on diffusion-weighted imaging
   • without midline shift or hemorrhagic transformation
   • infarct size less than or equal to 100 cc.
2. age 18 to 80 years
3. NIHSS 6 to 20
4. known onset time of acute symptoms
5. stem cell transplantation procedure must be performed within 24 to 72 hrs after stroke symptom onset
6. TPA infusion allowed

Exclusion Criteria:

1. experimental therapies during current hospitalization, e.g. intra-arterial or endovascular therapies
2. ischemic stroke in the past 3 months, any vascular territory
3. myocardial infarction in the past 3 months
4. any prior hemorrhagic or traumatic lesion of the brain on MRI.
5. seizure disorder
6. developmental delay
7. chronic kidney disease defined as baseline creatinine >1.4
8. hepatic disease or altered liver function as defined by SGPT >150 U/L and or T. Bilirubin >1.3 mg/dL at admission
9. pulmonary disease (e.g, COPD with oxygen-requirement at rest or with ambulation, moderate to severe asthma)
10. mechanical heart valve
11. any history of cancer
12. prior immunosuppression, including prior chemotherapy administration or current immunosuppression as defined by WBC <3 x 103 cells/ml
13. known HIV
14. hematocrit <10g/dl
15. uncorrected coagulopathy at the time of consent defined as INR >1.4; PTT>35 sec, or thrombocytopenia (PLT<100,000)
16. any hemodynamic instability at the time of consent (e.g, requiring continuous fluid resuscitation or ionotropic support), or hypoxemia (SaO2<90%)
17. persistent hypoxemia defined as SaO2 <94% for >30 minutes occurring at any time from hospital admission to time of consent
18. pregnancy or positive b-HCG
19. current participation in any formal research study
20. unable to return for follow-up visits for clinical evaluation, laboratory studies, or MRI evaluation
21. multiple anti-platelet medications (Aggrenox® is considered a single platelet agent.)
22. history of a transient ischemic attack (TIA) in another vascular area. TIA is defined as history of a transient episode of aphasia, limb weakness, or visual loss
23. unable to undergo MRI scan due to metal implant, claustrophobia refractory to anti-anxiety medication, weight greater than 300 pounds, or maximum circumference of 22.5 inches.
24. any other condition that the investigator feels would pose a significant hazard to the patient if enrolled.