Early reperfusion strategies in tandem with remarkable advances in drugs and devices for treating myocardial infarction (MI) have contributed to a reduction in early mortality, but cardiovascular disease remains the leading cause of death worldwide. Current management strategies cannot solve the problem of cardiomyocyte loss and consequent progression of heart failure. In this respect, stem-cell therapy has shown potential benefits for repairing the damaged myocardium. Mesenchymal stem cells (MSCs) have been considered to be attractive therapeutic candidates because of their high capacity for replication: paracrine effect: ability to preserve potency: and because they do not cause adverse reactions to allogeneic versus autologous transplants. Intracoronary injection of stem cells seems to be safe, but only one clinical trial using MSCs via the intracoronary route in the setting of acute myocardial infarction (AMI) has been carried out. The investigators therefore assessed the safety and efficacy of intracoronary autologous bone marrow (BM)-derived human MSCs in patients with AMI.

Inclusion Criteria:

• aged 18-70 years
• ischemic chest pain for >30 min
• admitted to hospital <24 h after the onset of chest pain
• electrocardiography showed ST segment elevation >1 mm in two consecutive leads in the limb leads or >2 mm in the precordial leads
• they could be enrolled in the study <72 h after successful revascularization

Exclusion Criteria:

• cardiogenic shock (defined as systolic blood pressure <90 mmHg requiring intravenous pressors or intra-aortic balloon counterpulsation)
• life-threatening arrhythmia
• impossible conditions for cardiac catheterization
• advanced renal or hepatic dysfunction
• history of previous coronary artery bypass graft
• history of hematologic disease
• history of malignancy
• major bleeding requiring blood transfusion
• stroke or transient ischemic attack in the previous 6 months
• structural abnormalities of the central nervous system (brain tumor, aneurysm, history of surgery)
• traumatic injury after myocardial infarction
• use of corticosteroids or antibiotics during the previous month
• major surgical procedure in the previous 3 months
• cardiopulmonary resuscitation for >10 min within the previous 2 weeks
• positive skin test for penicillin
• positive result for viral markers (human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and Venereal Disease Research Laboratory (VDRL) test)
• pregnancy, possible candidate for pregnancy or breastfeeding females
• drug abusers
• inappropriate patients to participate in the study according to the chief investigator