One of the challenges of stem cell therapy is to understand the fate of the injected stem cell. By labelling various stem cells with radioisotopes their fate (homing) can be demonstrated. In this study, we will develop and refine the existing techniques of stem cell labelling to various subtypes of stem cells namely- freshly aspirated bone marrow cells, cryopreserved bone marrow cells, g-csf mobilized peripheral blood stem cells and umbilical cord cells. After testing the labelling efficacy and viability, these cells will be injected in to the coronary arteries of patients with myocardial infarction who have undergone a successful revascularization either by angioplasty or thrombolysis. Homing of stem cells will be demonstrated by nuclear scan after the procedure. We are adapting techniques used to label cells for detection of infection and bleeding using nuclear scans for in vivo scanning. Also we are using Technetium instead of FDG which has very little radioactivity allowing us to work with the current cardiac labs with out having to reconstruct the labs with special shielding for radioactive compounds. Real benefit of stem cells then can be explored after demonstrating the proper homing.

Phase One: Four Different types of stem cells will be tested ( Freshly aspirated Bone marrow cells, cryopreserved cells, umbilical cord cells, Stem cells mobilised from bone marrow by g-csf, mesenchymal cells), and the efficacy of labelling documented and effect on viability noted. 3 samples of each type will be tested and the results will be documented. Different cells are being tried to test the efficiency of the labelling technique in different types of cells. This will provide the protocols for all future labelling studies. This will be conducted in collaboration between the stem cell department, nuclear medicine department and nuclear cardiology department.

Phase Two (Clinical Study):

This will be the pilot clinical study done alongside with the phase one study, and will enrol 10 patients with Recent Myocardial infarction ( within 3 months) . A small fraction of patient's own bone marrow stem cells will be labelled with Technetium 99m HMPAO. The labelled cells will be administered via the intracoronary injection along with the unlabeled stem cells. The localization of the radio-labelled stem cells in the myocardium will then be detected using the conventional Gamma camera.

Inclusion Criteria:

• Myocardial Infarction (< Three Months) with either angioplasty or thrombolysis done to open the infarct causing artery.
• Patent coronary arteries after the infarct
• Left ventricular dysfunction (ejection fraction < 50%)

Exclusion Criteria:

• Ongoing infection
• Obstructive coronary disease
• History of symptoms more than 3 months
• Any evidence of malignancy or other systemic illness.
• Cell yield less than 10 million cells

patients within 3 months following myocardial infarction