NBS10 (Also Known as AMR-001) Versus Placebo Post ST Segment Elevation Myocardial Infarction

Inclusion Criteria: 1. Age 18 years or older. 2. Acute ST elevation myocardial infarction meeting ACC/AHA criteria, with symptoms of chest pain within 3 days of admission. Criteria include (ST elevation \> 1mm in limb leads or 2 mm in two or more precordial leads, and increased levels of troponin, CPK MB or both). Chest pain syndrome can extend to more than 3 days prior to admission if its course is consistent with transient/intermittent ischemia rather than symptoms that are continuous suggesting ongoing infarction extending beyond 3 days. 3. Successful stent placement and reperfusion within 3 days of chest pain onset and with TIMI Flow score of 2 or 3 and infarct related artery (IRA) with \<20% stenosis after revascularization. 4. Wall motion abnormality associated with the target lesion 5. NYHA heart failure class I, II or III. 6. Study entry LVEF \<48% determined by CMR no sooner than 96 hours from stent placement. 7. Able to provide informed written consent and willing to participate in all required study follow-up assessments. 8. Subjects must have an INR ≤ 2.0 within 2 days of the bone marrow collection. 9. Subjects must have a Hgb ≥ 10 grams/dL, WBC ≥ 3500 cells/mm3, a platelet count ≥ 100,000 cells/mm3, serum creatinine ≤ 2.5, and total bilirubin ≤ 2.0 within 7 days of the bone marrow collection or by end of screening phase. 10. Expected survival of at least one year. 11. Females of child bearing potential agree to use birth control (barrier method accepted) for one month post bone marrow harvest. EXCLUSION CRITERIA 1. Continuous/ongoing chest pain - unremitting and unresponsive to nitroglycerin or rest - persisting 4 or more days before stent placement. If the chest pain syndrome is transient and/or intermittent - even if it began more than 3 days prior to admission - the patient is not excluded. 2. Subjects in cardiogenic shock (systolic pressure \< 80mm/Hg, on vasopressors, or intra-aortic counterpulsation) at the time of consenting. Subjects who recover from cardiogenic shock by the time of consenting are eligible. 3. Subjects unable to receive antiplatelet agents (e.g. aspirin, clopidogrel, ticlopidine, prasugrel, etc). 4. Subjects receiving warfarin who have an INR \>2 or with major bleeding requiring active transfusion support. 5. Subjects who require continuous anticoagulation during the time when the bone marrow harvest is scheduled, as heparin must be discontinued for 4 hours prior to and 24 hours after bone marrow harvest procedure. (See Appendix VII.) 6. Subjects with severe cardiac valvular disease expected to undergo surgery within 1 year. 7. Subjects with known severe immunodeficiency states (AIDS). 8. Cirrhosis requiring active medical management. 9. Malignancy requiring active treatment (except basal cell skin cancer). 10. Subjects with documented active alcohol and /or other substance abuse. 11. Females of child bearing potential unless a pregnancy test is negative within 7 days of the mini-bone marrow harvest. 12. Re-occlusion of the IRA prior to the infusion procedure. 13. Planned revascularization intervention during the next 6 months (A second PCI can be performed if done prior to qualifying CMR at least 96 hours post primary PCI). 14. Participation in an ongoing investigational trial. 15. Active or suspected bacterial infection requiring systemic intravenous antibiotics.